Respect Lumiya, Dark Lady of the Sith:

Power

Lumiya is powerful:

Lumiya has grown powerful in her seclusion, blending traditional Sith ways with new and dangerously innovative tactics.

Source: The Emperor's Pawns

Combat Skill

Lumiya's body is biologically enhanced and she is proficient in all combat forms:

Shira became proficient in all combat forms, from Echani to Noghri Stava, and her body was biologically enhanced.

Source: Star Wars Gamer #5

With the advantage of his unfamiliarity with a lightwhip, Lumiya defeats RotJ Luke, an equal with Darth Vader, in combat:

Gallery

Lumiya uses the exotic nature of her lightwhip to land blows on Nelani Dinn without effort. It is also stated that Lumiya was more skilled, as is already made obvious:

Nelani advanced. Lumiya retreated, slapping her thigh-digging her fingers through the cloth and into her thigh. She yanked, and suddenly in her hands was a whip. She flicked it back, preparatory to striking with it; its tendrils, for there were several instead of just one, spread out into something that moved like a weaponized cloud, some of them shining iron-like and jagged, some of them glowing like a lightsaber’s blade. Lumiya cracked the weapon forward; Nelani, her body language suggesting confusion as she faced this unusual weapon, twisted to one side, but one of the lashes, a metal one, grazed her face, drawing blood all along her left cheek. Nelani took a step back, shaking her head.

...

Nelani lunged forward again, spinning her lightsaber into a defensive shield.

Lumiya’s lightwhip flicked around the edges of the shield. Ends of several tendrils rapped into Nelani’s chest and right bicep, creating small blood and burn spots. Nelani cried out and danced back again, baffled by the older woman’s superior technique.

Source: Legacy of the Force: Betrayal

Lumiya and Alema Rar defeat Tresina Lobi, who makes use of both skill and unpredictability to make her two opponents hinder one another, but is ultimately defeated nonetheless:

The hum-and-sizzle of clashing weapons slowly brought her back to her senses, and she sat up to find Tresina Lobi spinning and parrying, slowly forcing Lumiya back, probing and feinting, trying to work her way past the crackling strands of Lumiya’s exotic lightwhip - and into the striking range of a lightsaber.

Alema summoned her own weapon back into her grasp, then stood and limped forward to help.

Lobi sprang into a backflip and sailed over a crackling whip strike. Then, as she was still descending, she extended a hand in Alema’s direction and used the Force to pull her into the path of the flashing strands. Lumiya barely managed to shut down the weapon before it struck, and even then the hot filaments cut through Alema’s robe, burning a rainbow of hot welts into her thigh and ribs.

Alema was still screaming when Lobi landed at Lumiya’s side. The Chev brought her lightsaber down, and Lumiya’s weapon arm-one of her many cybernetic parts - fell to the ground trailing sparks and hydraulic fluid.

Lobi reversed her blade instantly, angling for Lumiya’s torso, but Alema was already leaping forward to catch the Chev’s attack on her own lightsaber.

Lobi whipped her lightsaber around low, aiming at Alema’s knees and forcing her to leap back.

Alema pointed at Lumiya’s severed arm, then used the Force to send it spinning toward Lobi’s head. The Chev woman ducked easily, but that gave Lumiya time to call her lightwhip into her remaining hand and strike again. Lobi pivoted away from the attack. Alema sprang at her from behind, striking for the Chev’s thick neck, then cried out in surprise as a huge foot glanced off her ribs . . . and still sent her staggering back.

Lumiya seized the opportunity to launch a flurry of attacks, fanning the strands of her whip to make it more difficult to block, striking right and left to prevent the Chev from pivoting away again, slowly driving Lobi back toward Alema’s droning lightsaber.

Then, finally, Lobi faltered, gathering herself for a Force leap, but hesitating and retreating another step toward Alema instead. It was the moment Alema had been waiting for.

"You are good, Master Lobi - but not that good." Alema spoke in a Force whisper so soft that it was little more than a thought. "Even you cannot defeat two of us."

Lobi’s head snapped around, her eyes filled with confusion and doubt, and she spun into a whirling charge of crescent kicks and horizontal lightsaber strikes.

Alema held her ground, ducking a Iightsaber strike and letting a kick slip off her shoulder, then Force-slammed the hilt of her Iightsaber into the pit of the Chev’s stomach and spoke again in her Force whisper.

"No good."

Amazingly, Lobi stumbled only one step back . . . but that step was one too far. Lumiya’s lightwhip caught her across the back of the legs and severed them both at the knees. The Chev roared first in anger, then - as she dropped onto the stumps and pitched forward onto her hands - in agony.

It was a terrible sound to hear. Alema stepped forward and spoke once more in her Force whisper.

"There is no need to suffer." She swept her blade across the back of the Chev’s neck, and the head tumbled away. "Your fight is done."

Source: Legacy of the Force: Tempest

Lumiya duels evenly with Grand Master Luke Skywalker:

Luke silenced the Twi’lek with a bone-crunching back kick, then hurled himself at Lumiya, both blades striking for the kill. He knew better than to think victory would come so easily, but he had to keep her attention riveted on him until Mara struck.

Lumiya’s counter was, of course, masterful. She flicked her whip at Luke’s legs, forcing him into a high somersault that bought her half a second to spin away. He came down a couple of paces inside the cantina, framed in the hatchway and facing the murky corridor where Alema crouched, hidden inside her Force shadow.

Alema could have taken him at that moment. She had the cone-dart in the blowgun and the blowgun pressed to her lips, and Skywalker was so focused on Lumiya that he would never have sensed the dart coming. That was what Lumiya would want, what she expected.

But where was the Balance in that? Luke Skywalker had taken so much from her-the use of her arm, her nest, her identity-and it would not be right for Alema to simply kill him. She had to destroy him, to let him watch Mara die first so that when he died, he would know that there was no hope-so he would know that Lumiya had won, that the Sith would have his nephew and his son, and that the Jedi order would die with him.

So Alema held her dart, waiting motionless while Lumiya’s lightwhip flashed again and again, keeping Skywalker framed in the hatchway for her, striking at his flanks and head to keep him from pivoting or somersaulting or simply advancing out of her line of sight.

Finally Skywalker feinted a leap for the hatchway. When Lumiya made the mistake of trying only halfheartedly to block his "escape," he made an unbelievable parry across his body with his short blade, then spun into a slashing, whirling advance with his long blade.

Lumiya had no choice except to retreat. Skywalker vanished from the hatchway and out of Alema’s sight, then the last of the lightwhip’s metallic strands whirled past the hatchway. A fresh chorus of screams arose, and a jet of blood arced out of the cantina to splat down in a line of elongated red beads.

When Alema looked back into the cantina, it was to find Mara crouching opposite her, just inside the hatchway and facing away. Half a dozen meters beyond her, Skywalker and Lumiya were fighting a frantic battle in the midst of the crowd, Skywalker trying to remain in clear areas so no bystanders would be injured, Lumiya working to keep those same bystanders in front of her so Skywalker could not attack without cutting his way through them first.

Now was Alema’s chance - but it would not be enough to simply kill Mara. Alema was a Jedi, and Jedi served the Balance.

As she filled her lungs, Alema was also reaching out to Skywalker, sharing with him all the sorrow and loneliness and despair he had caused her - the shame and hopelessness and unending anguish.

A bolt of surprise shot through the Force. Skywalker’s eyes widened and slid toward the hatchway - and that was all the opening Lumiya needed.

The lightwhip cracked again, wrapping Skywalker in a fiery cage of light and leather. The short blade went flying, taking along the hand that had been holding it, and Sky-walker’s robe fell away below the armpits in ribbons, leaving the air pink and smoky with blood and charred flesh.

...

And time was something Luke did not have. He could feel that in the fire eating his lungs, in the raw nettling of his flesh. His breath came in inadequate gasps, and his blood was bubbling from his side in a pink froth. He was calling on the Force to keep fighting, drawing it through himself faster than his body could endure, literally boiling his own cells. At most, he had another minute of fight in him . . . maybe less.

Luke had to end this now.

He blocked a pair of crackling energy strands with his lightsaber and flung them aside, then launched himself across a daqball table toward Lumiya. She countered by pivoting away, bringing between them a Twi’lek serving girl. He could have continued the attack, slicing through the chests of both shield and captor, but even desperate, he could not kill a hostage. He threw himself into an aerial cartwheel and came down on a slick, utensil-strewn floor squarely facing Lumiya.

Her hand flicked, and the lightwhip came arcing toward his head. Luke dropped to his haunches and let it crackle past overhead. Then, when Lumiya started to back away from the expected lunge at her midsection, he hit her hard with a Force shove and spun her half around. She crashed into a drink table and nearly fell, but quickly brought her hostage around to protect her from an attack.

Luke smiled and raised his arm, pointing his lightsaber toward the serving girl, then using the Force to wrench her free of Lumiya’s grasp, he sent her flying across the claqball table. She crashed down on the other side in a heap, screaming in terror but far safer than she had been a moment earlier.

By then Lumiya had recovered from her stumble, and the lightwhip was snaking back toward Luke. He sprang into a round-off, wrapping the tip of his blade into the crackling strands as he passed over upside down. He landed on the claqball table’s squishy surface and jerked backward with all his might.

And that was when his mangled body failed him. Instead of yanking the weapon from Lumiya’s hand, his lightsaber slipped out of his own grasp and went flying into the shadows. Luke cursed in disbelief-then rolled off the table in a backward somersault.

Even that turned into a disaster. He landed on the body of one of Lumiya’s original victims and-too weak to steady himself-hit the floor with an audible thump. He could sense Mara out in the corridor, concentrating intently on something, very frightened and urging him to wait for her, not to press the attack until she was there.

There was no chance of that. Luke’s strength was failing so fast that he feared Jacen’s betrayal would cost him his life. And when Lumiya was done with him, she would be free to go attack Mara, as well. His chest tightened with an emotion that might have been anger or sorrow or fear-and was probably all those things at once. Jacen had betrayed them . . . which could only mean that somewhere along the line, Luke had failed Jacen.

Lumiya must have suspected a trap, because when Luke failed to rise immediately, she did not rush to attack. Instead, she called, "It’s not too late, Skywalker. Let me kill you now, and everyone else survives. Even Mara."

"Very generous." As Luke replied, he was inspecting the cantina floor, searching for the shoto he had lost when Lumiya took his cybernetic hand. "But I don’t. .. think so. You can’t have . . . Jacen."

"Jacen?" Lumiya let out a cold laugh. "What makes you think this is about him?"

"Your involvement with GAG." He wasn’t having much success looking for his lightsabers; the blades had deactivated as soon as they left his grasp, and the cantina floor was too littered in debris and shadow for him to find anything. "Who else could give you ... an apartment? Who else could give you access to ... their files?"

Again, that cruel laugh. "Indeed." The lightwhip’s crackling grew deeper as Lumiya shortened the strands for easier control. "Who else has access to Jacen’s codes? Who else could give orders to GAG officers in Jacen’s name?"

The questions caught Luke like a kick in the stomach. He knew that Lumiya was only trying to hurt him, that her implications were likely more false than true. But the possibility explained too much . . . and now that he thought back on Ben’s behavior over the last several months, he had to admit that he had seen too much of that possibility himself.

Something crunched on the floor as Lumiya circled the base of the claqball table. Luke gave up his search for his shoto and began to look for another weapon. He had not brought his own blaster into the cantina, prefering light blades instead, but the body he had fallen on was almost certainly a spacer, and spacers always carried blasters.

"You’re lying." Luke found the spacer’s belt and followed it to a holster. "Just saying that... to hurt me!"

"Does that make it a lie?" Lumiya asked. "You’ve caused me a lot of pain over the years, Skywalker. What better way to repay it than bringing your family legacy full circle?"

Luke knew she was only trying to twist the vibroblade, to hurt him as much as she could before she killed him- but he stuck his head up anyway.

"Stop it!" he yelled, with real anger. "You’ll never make a Sith of my..."

Luke never had a chance to say son. All he saw was the bright glow of Lumiya’s lightwhip snaking across the claqball table barely centimeters above the surface, and he knew that his reflexes were just too slow right now, that he could not duck quickly enough to keep the whip from slicing into his brain.

So Luke simply fell backward, closing his eyes against the crackling glow as the strands swept past a finger’s width above his nose, bringing up the blaster he had taken from the dead spacer’s holster, allowing the Force to guide his hand, squeezing the trigger three times before he felt Lumiya’s shock in the Force, then squeezing it twice more before he heard her body hit the floor.

And suddenly Mara was screaming at him from across the cantina, flooding the Force with alarm. "Stop firing!"

Source: Legacy of the Force: Tempest

During the above fight, Mara muses that she can only hope an injured Luke is capable of holding Lumiya off:

Mara only hoped that Luke could hold Lumiya off until she finished.

Source: Legacy of the Force: Tempest

Zekk states that he does not believe that a team consisting of himself, Jaina Solo, and Jagged Fel to be a match for Lumiya, claiming that she fought Luke to a standstill and that she is "Master level":

"I don't think the three of us are a match for Lumiya. She fought the Grand Master to a standstill. She's Master level. We're two Jedi Knights and one Force-blind space jockey."

Source: Legacy of the Force: Exile

Lumiya is again stated to have fought Luke to a standstill, and is stated to be one of the galaxy's deadliest killers:

In addition to being a cocky teenager alone in a galaxy at war, Ben might now be the target of one of the galaxy's deadliest killers-a woman who had fought Luke to a standstill mere weeks before.

Source: Legacy of the Force: Exile

Lumiya engages Luke in an inconclusive fight:

As Han and Leia approached, the nature of the battle before them changed in an instant. Abruptly Luke was drawing and igniting his second lightsaber, the half-length shoto, and using his primary lightsaber to deflect a weapon that looked oddly like Lumiya’s lightwhip.

Han squinted. The wielder was Lumiya, though her skin was dark. He raised his blaster and fired, but Lumiya must have been aware of him; she simply twisted aside and the bolt caromed off the floor, then passed through the chest of the six-meter hologram of an admiral that dominated the center of the room.

Mara, nearly surrounded by security agents, was batting their blasterfire back at them with her own lightsaber. Leia angled away from her, toward Luke-and then let out a surprised cry as a low table slid into her path, too suddenly for her to vault or sidestep. She tripped but came up on her feet and lit her lightsaber.

She stopped abruptly and stared to the left. Han followed her gaze ... to see Alema Rar emerging from wall-side shadows, an odd smile on her lips, her lit lightsaber in her hand.

"Mine," Leia said, and leapt forward.

Han ignored her. He fired at the Twi’lek, but Alema casually caught the bolt with her lightsaber, then began spinning her blade in a defensive pattern as Leia reached her.

* * *

"I guess this settles the question of whether you're dead or not," Luke said. He caught another crack of the lightwhip On his long blade, darted in close, slashed at Lumiya with the shoto. But with an exertion through the Force, she lifted a severed human head into the path of the blow, and Luke's attack sent the head spinning through the air. It landed on a table stacked with food.

"Of course," Lumiya said. "I thought you knew. I am dead. I have been for decades."

"Then lie down and let us throw dirt on top of you." With a similar telekinetic exertion, Luke whipped the tablecloth from beneath all the platters and hurled it at Lumiya. It swept upon her from behind, but she cracked her whip backward, cutting the tablecloth in two, then continued the maneuver into a forward stroke. Luke deflected separate lightwhip tendrils with his two blades.

"You really do hate me, don't you?" Lumiya asked.

"You've given me plenty of reasons to. But no. I don't reciprocate your hate." Luke leapt over another sweep of tendrils, coming down atop a chair and leaping free of it as Lumiya's follow-up attack disintegrated it. He landed lightly, poised.

"I don't hate." She lowered her whip. "I'm sorry you think that of me. I haven't hated for ... a very long time. Yes, I've tried to kill you-but that was professional. Not personal."

Luke held up his own weapon long enough to deflect a stray blaster bolt, a security agent attack that merely strayed too near him, then lowered the lightsaber, matching Lumiya's action. "You don't hate. Somehow I don't believe that."

"We belong to rival schools, Luke. That's all. Shall I prove it?"

"Sure."

Lumiya deactivated her lightwhip and wrapped it around her waist. She gestured, palms up. "Kill me now, if you want."

Source: Legacy of the Force: Exile

Lumiya fights Mara Jade Skywalker and flees with the aid of Ship:

Mara's autopilot kicked in and she was the Emperor's Hand again, silent and focused. There was nothing worth saying anyway. Amateurs gave speeches; professionals got on with the job.

She Force-leapt five meters at Lumiya, slashing down right to left, two-handed. The stroke—all power, no finesse—clipped the Sith's headdress as she sprang back, slicing off a section. Lumiya's eyes widened, pupils dilated, but she was already whirling her lightwhip about her head. The tails crackled and hissed, missing Mara only because she threw all her energy into a Force push to slow them a fraction.

Mara didn't take that weapon lightly. It was the worst of both worlds, leather strips studded with impervious Mandalorian iron fragments and tendrils of sheer, raw, murderous dark energy. Mara drew her blaster and rolled under the hull of the ship next to her. The light-whip gouged through the durasteel with a shriek of tearing metal, filling the air with the smell of hydraulic fluid, and the spurt of liquid turned into a torrent that began spreading in a thick pool. As Mara rolled clear on the other side of the ship, Lumiya landed heavily on both feet and brought the whip down so close to Mara's head that she felt the rush of air on her right cheek like a breath. The crack was deafening.

Mara wasn't even thinking when she aimed the blaster. Lumiya's whip hand was raised to throw as much weight as possible from the back stroke. A puff of white vapor burst from Lumiya's shoulder, and she staggered a few paces.

Metal. Maybe I hit metal.

Maybe she had, because Lumiya teetered for a second but came right back. Mara sprang horizontally from a crouch and cannoned into Lumiya's legs with all the power she could muster from the Force. She hit solid durasteel. Blood filled her mouth but she couldn't feel a thing—yet. Clinging to Lumiya's knees with one arm, denying her the space to swing the whip, she brought her down like a felled tree before smashing her head into the woman's face.

And that hurt. Oh yes, Mara felt that. She'd caught not Lumiya's nose but the cybernetic jaw, and it cut deep into her forehead. Fighting on pure reflex now, part stunned, she killed the lightsaber blade for a second and held the hilt like a dagger, stabbing it down into Lumiya's chest before flicking the energy back on. Lumiya pulled to the side as the blade punched through flesh. Mara smelled it. She flicked off the blade to pull back again, triumphant.

I've done it. Dead. Dead, you—

But Lumiya was screaming, and that wasn't right at all. The scream seared through Mara's spinning head. It was more than sound. It was—

Mara scrambled to her knees to look down at what should have been a dead woman, and stared into green eyes that were utterly devoid of any emotion, and then the world darkened like an eclipse.

Maybe I'm the one who's dead.

Something hit her square in the back, pitching her forward onto Lumiya. Mara struggled to turn over without letting go of either lightsaber or blaster, but something coiled around her neck and jerked her backward. The lightwhip was still in Lumiya's fist, she could see the thing, she could see it, so what was around her neck, choking her? She felt as if she was flying backward at high speed, and then she hit something so hard that it punched every bit of breath out of her lungs and left her gulping for air.

A second or two was all it took. Mara lay trying to suck in air in painful, straining gulps, eyes stinging, and saw Lumiya's boots run past her face at a stagger, missing her by centimeters.

What's in my eyes? What's stinging?

She raised her hand to rub them and her knuckles came away red and wet. It was blood. The last thing she saw as she looked up was the orange sphere, that impossible Sith ship, soaring vertically into the air and extending webbed vanes like living wings.

Source: Legacy of the Force: Sacrifice

Lumiya briefly contends with a bloodlusted Luke Skywalker, then stalemates him in a saberlock before losing her footing:

She drew back her arm and brought the lightwhip crackling through the air, missing Luke by centimeters. He lunged at her again and again, driven back each time. She'd slow sooner or later.

But so would he.

Then, as she began to raise her arm again, he ran at her, so close in that she couldn't get the whip traveling at its maximum lethal speed. He forced her back, step by step, as she tried to maintain the distance she needed.

One—two—three—four; she blocked him, handle held this way, then that, using the whip like a short lightsaber to deflect him, but Luke didn't pause or shift direction to wrong-foot her. He drove her like a battering ram toward the edge of the mesa, pushing her within meters, then a step, of the edge.

Lumiya held the whip handle in both hands like a staff and blocked his downward sweep. For a moment they were locked in a stalemate, pushing against each other and grunting with the effort, with only the sounds of exertion because they had nothing left to say to each other.

Her rear foot began to slide backward as she struggled for purchase. The edge of the mesa was cracked and fissured. The smooth glittering stone began to crumble. Luke reached out and caught her hand as she fell, whip tumbling and bouncing down the steep rock face into oblivion. He leaned back, all his weight on his heels, knuckles clenched white with the strain of holding her weight, and for a second he wanted to see her face dwindling as she fell to her death, mouth open in a scream, but that wasn't the way to end this.

"I'd never let you fall," Luke said, and pulled her back to safety. As she straightened up, he looked her in the eyes—calm, eerily calm—and swung his lightsaber in a single decapitating arc.

Now he could breathe again.

Source: Legacy of the Force: Sacrifice

Physical Attributes

Strength

Lumiya stalemates Luke in a contest of strength for a moment before losing her footing on uneven terrain:

Lumiya held the whip handle in both hands like a staff and blocked his downward sweep. For a moment they were locked in a stalemate, pushing against each other and grunting with the effort, with only the sounds of exertion because they had nothing left to say to each other.

Source: Legacy of the Force: Sacrifice

Speed

Lumiya evidently moves faster than Nelani Dinn, avoiding her lightning-fast strike:

She struck at Lumiya.

***

Nelani's lightsaber blow was lightning-quick, but by the time it landed the older woman had twirled to one side, positioning herself behind a bust. The glowing blade sliced off the marble top of the head of some long-dead Rodian scholar.

Source: Legacy of the Force: Betrayal

Luke knows that he cannot blitz Lumiya:

Luke silenced the Twi’lek with a bone-crunching back kick, then hurled himself at Lumiya, both blades striking for the kill. He knew better than to think victory would come so easily, but he had to keep her attention riveted on him until Mara struck.

Lumiya’s counter was, of course, masterful. She flicked her whip at Luke’s legs, forcing him into a high somersault that bought her half a second to spin away.

Source: Legacy of the Force: Tempest

Lumiya capitalizes on a distraction to wrap Luke in her lightwhip and sever his hand before he can react:

As she filled her lungs, Alema was also reaching out to Skywalker, sharing with him all the sorrow and loneliness and despair he had caused her - the shame and hopelessness and unending anguish.

A bolt of surprise shot through the Force. Skywalker’s eyes widened and slid toward the hatchway - and that was all the opening Lumiya needed.

The lightwhip cracked again, wrapping Skywalker in a fiery cage of light and leather. The short blade went flying, taking along the hand that had been holding it, and Sky-walker’s robe fell away below the armpits in ribbons, leaving the air pink and smoky with blood and charred flesh.

Source: Legacy of the Force: Tempest

She casually dodges a shot from Han Solo while fighting Luke:

Han squinted. The wielder was Lumiya, though her skin was dark. He raised his blaster and fired, but Lumiya must have been aware of him; she simply twisted aside and the bolt caromed off the floor, then passed through the chest of the six-meter hologram of an admiral that dominated the center of the room.

Source: Legacy of the Force: Exile

Durability

Due to her mostly cybernetic body, Lumiya has enhanced durability.

Lumiya shrugs off being hit by a blaster bolt:

Lumiya recovers from being shot by a blaster bolt in a second:

Mara wasn't even thinking when she aimed the blaster. Lumiya's whip hand was raised to throw as much weight as possible from the back stroke. A puff of white vapor burst from Lumiya's shoulder, and she staggered a few paces.

Metal. Maybe I hit metal.

Maybe she had, because Lumiya teetered for a second but came right back.

Source: Legacy of the Force: Sacrifice

Force Sense

Lumiya Senses Jacen's anxiety:

"I could sense your anxiety."

Source: Legacy of the Force: Bloodlines

Force Concealment

Lumiya is able to walk in the Jedi Temple without being her dark signature being detected by anybody. Even Jacen Solo, despite already knowing Lumiya's true nature, had been unable to sense her true nature:

Lumiya walked beside him up the promenade leading to the Temple, and it felt as if she had cloaked herself completely. He could sense her unease, but any hint of darkness had been reduced to no more than the simmering passions found in any ordinary untrained human being. She passed through the huge doors of the imposing entrance and reacted just as any ordinary person with no Force sensitivity would: she stopped in her tracks and stared.

Source: Legacy of the Force: Bloodlines

Jacen knows that Lumiya can hide in the Force, and contemplates that she is using it to the point where even Jacen cannot sense her:

"Lumiya?"

Silence.

She could hide in the Force, too. She thought he was letting his concentration wander. She probably couldn't resist finding out where he was going.

Source: Legacy of the Force: Sacrifice

Hibernation Trance

Lumiya is able to use a hibernation trance in conjunction with her altered physiology to survive in space:

Her altered physiology, coupled with her ability to enter a Force trance enabled her to survive in space.

Source: Star Wars Gamer #5

Force-flash

Force-flashing is a Force technique that can temporarily disable security holocams by causing static, making it appear to be a malfunction.

Lumiya utilizes a Force-flash to prevent a security camera from recording her image:

"I’d recognize her if I saw her." Luke went to the Bith’s side and saw that he was calling up last night’s video feed from the anti-terrorist cams that had been installed to protect Fellowship Plaza. "But she won’t be visible."

"She won’t?"

"No. She’s too skilled for that." Mara joined them and held her hand out for the datapad. "May I?"

Tozr ruffled his cheek flaps, then reluctantly passed over the datapad. Mara began to punch keys, bringing up the feed from the entrance closest to the Jedi Temple. It didn’t take long to spot Ben entering the park and Master Lobi trailing him, following a discreet distance behind and taking care to remain in the shadows. But they spotted no hint of Lumiya-or of the second killer-even when Mara brought up the feeds from the next two cams.

Luke checked the time stamp at the bottom of the screen, then said, "It’s too early. Tresina’s message didn’t come in until nineteen twenty-two."

"What message?" Raatu asked.

"She clicked in with a partial message saying she had spotted Lumiya," Luke replied.

"What else?" Raatu demanded.

"That’s it," Luke said. "Just that I was right, Lumiya was watching Ben. Then she cut it short.

""But it doesn’t look like this Lumiya was following your son when he left the Temple," Tozr said. He reached over to tap the screen of the datapad. "So she was waiting for him inside the plaza."

"It would seem so." The edge in Mara’s voice was as cold as the knot in Luke’s stomach. "I don’t like it. She knew where he was going to be."

"We said this was an ambush," Raatu reminded them. "Both killers were waiting for Master Lobi in the hedges."

"That’s the way it looks, all right," Luke said. He turned back to Mara. "Lumiya had to enter the plaza somewhere."

Mara began to bring up feeds from the other entrances and run through them at high speed. Finally, a line of static flashed across the screen, and she froze the picture and checked the time code.

"Nineteen fourteen," she reported.

"Eight minutes before Tresina’s message," Luke said. "That fits."

"But that’s just a power glitch," Tozr said, still looking at the datapad.

"It’s a Force-flash," Luke corrected. "And it can be used to prevent a security cam from recording your image as you pass through its field of view."

Source: Legacy of the Force: Tempest

Telekinesis

Telekinesis is the ability to manipulate objects or beings with the power of one's mind.

Lumiya calls Leia's blaster into her hand:

Lumiya hurls Jacen out of the way of a blowgun dart:

Then Jacen cried out and flew backward, as though hurled by an invisible hand, and the dart flashed past, eliciting a liquid roar of pain as it disappeared into the enormous eye of the World Brain.

...

Five meters across the Well’s edge-and one balcony up-stood the fog-blurred silhouette of a thin woman in a scarlet robe. Her arm was still extended toward the slime pool, leaving no doubt that she had been the one who Force-hurled Jacen to safety.

Lumiya.

Source: Legacy of the Force: Tempest

Lumiya casually hurls a severed human head into the path of Luke Skywalker's attack:

But with an exertion through the Force, she lifted a severed human head into the path of the blow, and Luke's attack sent the head spinning through the air. It landed on a table stacked with food.

Source: Legacy of the Force: Exile

Telepathy/Empathy

Telepathy is the ability to manipulate or communicate thoughts and mental impulses. Empathy is similar but relates to emotions rather than mental thoughts.

Lumiya redirects a number of people's fear and anger towards Luke:

Their eyes were distant and their mouths uniformly twisted into the same angry snarl, and Luke realized that Lumiya was using the Force to redirect their fear and anger toward him. Clearly, she did not intend this to be a fair fight. . . any more than he and Mara did.

Source: Legacy of the Force: Tempest

Battle Meditation and Coordination

Lumiya knows an extremely advanced form of Battle Meditation, allowing for extensive mental coordination and sensing that vastly transcended ordinary Battle Meditation:

Lumiya had promised him a battlefield awareness and judgment that made ordinary battle meditation look like a finger painting—to sense and coordinate by the power of his mind and will alone, a power that only came to fruition in the Master of the Sith.

Source: Legacy of the Force: Sacrifice

Force Illusion

Lumiya's greatest ability with the Force is the ability to create all forms of illusions, a technique she mastered. She also mastered Darth Vectivus's Force Phantom technique.

Lumiya created a Force phantom of Ben Skywalker that Nelani Dinn had been thinking was the real Ben, even though the two were hundreds of meters apart, talking to phantoms of one another:

"Where’s Ben?" Jacen asked.

Nelani shook her head. "We were separated."

"You were never together," Lumiya said. "When you were talking to Ben and he to you, you were actually hundreds of meters apart, talking to Force phantoms of each other. A trivial thing to arrange in this place, where there’s so much energy to manipulate." She returned her attention to Jacen. "Energy you could use, in the name of improving people’s lives, if you chose to."

Source: Legacy of the Force: Betrayal

Lumiya creates, sustains and directs hundreds of Force phantoms at once, in different shapes and sizes, across the galaxy. In the second quote, it is also seen that the "Nelani" itself was a phantom, which validates Lumiya's words above. As the Nelani vanishes, it is replaced by an illusion of Mara:

Above him, ten meters up, a pair of eyes stared down at him. They glowed blue in the reflected light of his lightsaber blade. They were not human eyes, but slitted and triangular.

Beyond them were more, hundreds of pairs of eyes, cool and unblinking.

Ben shook his head. He’d had that portion of stone wall in sight as he’d approached the wall. There had been no creatures there at the time. He reached out for them within the Force, and could feel them there, hundreds of them, strong in dark side energy."Not good," he said.

"Drop," Nelani said.

...

Now Ben could hear rustling, hissing that sounded like muffled, sibilant speech, from above - from hundreds of sources above.

"They’re going to swarm us," Nelani said. She sounded rattled.

As if her words were a cue, a form of permission, the eyes above suddenly descended en masse, pouring downward as if carried by a waterfall. Nelani’s lightsaber snapped into life, adding a yellow-white glow to the proceedings. Ben raised his own blade in a high defensive stance.

The first wave of descending creatures broke before it reached the Jedi, splitting into two streams, each headed a different direction parallel to the stone face. But two of the creatures did not veer away. One came at Ben, one at Nelani.

Ben darted to one side-or tried; despite having some experience in low-gravity environments, he wasn’t accustomed enough to them for appropriate movements and tactics to be instinctive. He pushed off but floated mostly upward, straight toward his attacker.

No matter. The creature - revealed in the light of Ben’s lightsaber to be a fleshy stretched wing with eyes at one end, a tail at the other, and a wet mouth toward the center of its underside, something like a mynock-flew straight at him. Ben swung, felt his blade cut into skin and meat, and was propelled back down by the impact as the two halves of the beast hurtled lifelessly past him, one to either side.

The soles of his feet hit stone again. He absorbed as much of the impact as he could with his knees and did not bounce up very far this time.

The two mynock halves were partly embedded in the stone, and as he glanced at them, they slipped beneath the stone’s surface like two halves of a boat sinking. They left nothing behind-no blood, nothing.

"They’re not real," Ben said.

"Projections of the Force," Nelani answered from behind. "So they can’t really hurt us, right?"

"Wrong." Her tone chided him. "You know better than that. It’s like saying A laser beam can’t hurt me-it’s only light, right?"

"I was just hoping."

"Oof." Nelani sounded as though she’d taken a shot to the gut, and her lightsaber winked out instantly.

Heedless of the swarms of mynocks overhead, Ben spun, the motion bouncing him a couple of meters up.

Nelani was gone. In her place stood Mara Skywalker. Her eyes glittered with anger and her body language suggested punishment to come. Her lightsaber, in her hand, was unlit.Ben floated back to the ground. "You’re not my mother," he said."Good," she said. "Then it won’t be a family crime to cut you down." She ignited the lightsaber, and its blade glowed red.

Source: Legacy of the Force: Betrayal

Lumiya creates Force Illusions of Jacen that Luke duels briefly (Luke might have even been fooled into thinking it was a real entity, since Luke actually dueled him and "Sensed" his presence), as well as an illusion of Ben that Mara duels briefly:

Luke felt a presence, the arrival of someone strong in the Force. He opened his eyes.

Hovering over the floor in front of him, meters from him, was his nephew and onetime prize pupil, Jacen, lightsaber lit in his hand. Except it was not truly Jacen; whoever it was reeked of dark side energy, and his stare promised only malevolence. "Not nice," the false Jacen said.

Luke rose. "Who are you, really?"The not-Jacen snorted. "You barely exist. You don’t need to know." He took an odd, gliding step forward-it was only the slightest of exertions, but he floated meters toward Luke.

Luke lit his lightsaber.

The not-Jacen struck, a fast, powerful lateral blow that Luke met with little effort, without conscious thought. Not-Jacen’s blade was immediately in guard position for an anticipated counterstrike, but Luke held back. Oddly, the force of the impact sent his opponent floating backward. Not-Jacen drifted until he hit the corridor wall, which checked his motion, and he floated gently to the floor.

Then Luke heard the humming and chattering of lightsabers in conflict. The muffled noise was coming from his own quarters.

Mara rose, throwing her covers off in a move designed to whirl them over attackers and give her a moment to collect herself. As she came up on her feet, she reached out and pulled through the Force, and was rewarded with the comforting weight of her lightsaber hilt thumping into her hand.

The room was lit in hues of red by the lightsaber blade hovering in the middle of the room. It was held by a small, misshapen form whose feet were well off the ground. The figure was faced away from her as she rose, but now, boosted by a little push in the Force that Mara could detect, it turned in midair and presented glittering red eyes to her.

It was a boy, maybe thirteen years of age. Its features resembled Ben’s but were twisted in anger, an anger that looked like it had years of abuse, jealousy, and rage behind it. The boy’s hair, unlike Ben’s, was blond, styled in a sort of bowl cut with bangs, and Mara realized with a shock that it was the hairstyle of Luke Skywalker in his youth-she’d seen the holos of him in his adolescence. Worse, for she’d seen those holos as well, it was the hairstyle of the juvenile Anakin Skywalker.The boy drifted gently down to the floor. "You’re not my mother," he said. His voice was a serpentine hiss, full of loathing.

"Good," Mara answered. "Then it won’t be a family crime to cut you down." She lit her lightsaber, and its blue glow clashed with the red already suffusing the chamber.

The blond boy leapt at her, lightsaber extended in a spear-like thrust, but as he came within range he spun the blade around and low in a sweeping cut.

Mara danced back and to one side, out of range of the attack, and negligently waved a hand at the boy. His eyes widened as her wash of Force energy caught him and threw him against a wall.Against-and through. He disappeared and the glow of his light-saber vanished with him.

Mara could still feel his presence, his proximity, even if she could no longer say in which direction he was to be found. She brought her lightsaber up in a defensive posture and waited.

Then she heard the clash of lightsaber blades from outside her quarters, in the corridor.

Source: Legacy of the Force: Betrayal

Similarly, Ben fights an Illusion of his mother, Mara Jade:

As the Sith Mara’s Force attack swept him away from her, Ben switched his lightsaber off. Whirling within the power of her attack, instead of fighting against it, he added some Force energy of his own-shoving him laterally across the direction of her attack, and suddenly he was being swept at almost right angles to the direction she’d sent him. For half the duration of each spin he was making, he could see her, illuminated by her lightsaber, and now she was looking in the wrong direction; his maneuver had worked.

He slammed into a wall of stone, managed to keep from grunting in pain. He rebounded off the surface and began to drop toward the floor below; he calculated it as only ten meters down, an easy drop in this gravity. When he hit the ground, he did so with a silence that would probably please his real mother.

In the distance, the Sith Mara stood ready, her head turning this way and that, seeking for him with her Force-senses as well as with her eyes. Ben tried to blank out his mind, to erase his thoughts, to give her nothing to look for. And he wasn’t using the Force; that would help.

But he was the only person within hundreds of meters of the Sith Mara. That should make it child’s play to find him . . . yet somehow it didn’t, and she kept looking.

Ben made one long lateral bound, circling the Sith Mara’s position. In that time, Sith Mara stopped moving; she stood stock-still, her lightsaber down at an angle suited to bringing it up in a blow or an umbrella-style defensive posture, and Ben suspected that her eyes were closed.

Silently, he launched himself forward. He brought his unlit light-saber back at a ready-to-strike angle and kept his thumb on the power stud.

His jump was accurate; he didn’t need to correct it with little Force adjustments. He flew directly toward her, closing the gap between them as fast as a thrown zoneball.

Then he was near enough to see her face, her features. She was at rest, her eyes closed.

At peace. This wasn’t his mother, but it was his mother’s face, and there was no evil in it, no Sith malevolence.

He couldn’t thumb on his lightsaber and kill her. He just couldn’t.

She turned toward him and her eyes opened, red-glowing as before. She continued her turn into a spin. A chill of fear cut through his middle and he knew that her lightsaber blade would follow where the chill had been.

But it was her foot that came up, snapping into his gut with the power of a combat droid’s pistolling arm.

In slow motion, he felt the wind leaving his lungs, felt himself folding over her foot, felt his internal organs compress and bruise. Then he was flying away, blackness washing across his eyes where the image of his mother had been.

Source: Legacy of the Force: Betrayal

Jacen Solo comments on the fact that Lumiya is skilful in the art of forming Illusions:

Good actress. Lumiya’s skill at creating illusions extended into the physical world, as well.

Source: Legacy of the Force: Bloodlines

Lumiya is able to form Illusions that look visually enhanced when viewed through reflective surfaces - for instance, a Mara illusion seemed to be more beautiful, have a deeper red, have less lines on her face, and so on:

Luke turned back toward the living room and saw Mara’s reflection staring at him out of a mirror. She seemed more beautiful than ever, her hair a deeper red, her face a little fuller and less lined.

Source: Legacy of the Force: Tempest

Lumiya can create realistic Illusions from the Dark Side nexus of the Home:

He’d known about her ability to project realistic Force phantoms from her home, an asteroid suffused with concentrated Force energy.

Source: Legacy of the Force: Exile

Lumiya uses the Force to create illusions of Klauskin's dead wife, making her appear to him at varying times, and after not being in view, vanishing into the Force. Her repeated usages of this technique causes Klauskin to become insane:

Lumiya gave Klauskin one last, sweet kiss as he stood on the walkway outside the mental hospital. The shaking her real body was experiencing almost reflected itself in trembling in Edela’s arms, but she maintained ruthless control.

Then she let Edela fade away to nothingness. Her consciousness roared back into her own body.

...

Matric Klauskin, former commander of the Second Fleet’s Corellian task force but for the last several weeks a patient in this too-sympathetic prison, awoke. The small room been given was, as always, dark and quiet, its few items of furniture reflecting white gleams from the city lights filtering in through the transparisteel viewport. Everything was as it should be.

Or perhaps not. The door was open.

He frowned. The door opened only when the doctors or nurses came for him, or when his caseworker from the Alliance’s naval administration visited to reassure him that all was well; they hadn’t forgotten him.

But now the door was open and no one was entering.He sat up, his sheet falling from his chest, and realized that someone was standing beside his bed. He looked up.

It was Edela. Of course it was Edela. His treatment here was all about his wife. Now she smiled down at him, patient and loving as always. Tonight she wore a shimmering synthsilk gown of burgundy.

She had lost weight, diminishing from the pretty but distinctly overweight woman she had been the last time he’d seen her to a figure he could describe as "pleasingly plump." The gray was gone from her hair, too, and he realized belatedly that she wasn’t just slimmer, she was younger, she looked as she had a mere five or ten years into their marriage."Hello, dear," he said. "You realize you’re dead."

Her smile broadened. "Of course I’m dead. I’ve been dead for years. But it doesn’t mean I don’t exist."

"Well, that’s the point, isn’t it? The doctors all say that you don’t, that your very existence rests only in my mind. But they say I’m getting better."

"I don’t exist just in your mind. I exist in fact. Phantoms of the mind can’t open a door and free you, can they?"

Klauskin looked again at the door. It remained resolutely open. "That just means I’m dreaming again. It’s really not open."

Source: Legacy of the Force: Exile