In what is likely to be my final respect thread for an ancient Sith Lord, I present a compilation of one of the lesser known, but nonetheless most powerful of all Sith Lords - Karness Muur, who is the most long-lived of any Sith Lord. In life, he was one of those who created the Sith Order and its basic tenets and philosophies, and the time of his spirit's vanquishing, more than seven millennia later, is around the last time the Sith have appeared in the Expanded Universe.

Respect Karness Muur:

Power

Karness Muur is regarded as a powerful Sith Lord and his power is compared to that of Marka Ragnos and Freedon Nadd's:

The spirits of powerful Sith Lords such as Marka Ragnos, Freedon Nadd, and Karness Muur influenced galactic events and inspired others to do evil long after their physical deaths.

Source: The Old Republic Encyclopedia

Muur was a powerful figure in Old Republic history, along with the likes of XoXaan and Remulus Dreypa:

"The story begins not with Sith -- but with fallen Jedi. And a gathering of such warriors, nearly four thousand years ago -- at the Battle of Corbos. Many powerful figures fought there. Karness Muur. Remulus Dreypa. XoXaan."

Source: Lost Tribe of the Sith: Spiral: Part 2

Darth Wyyrlok III regards the original Dark Jedi Exiles as powerful dark siders:

"These powerful dark siders made a last stand on the planet Corbos against Jedi hunters and powerful dark side rivals. We know this ended the Hundred-Year Darkness."

Source: Legacy 30: Vector: Part 11

Emperor Vitiate regards Karness Muur's spirit as powerful enough to pose a threat to him when he returns to the known galaxy:

The Emperor knew the spirits of the ancient Sith Lords could be a threat to his power when he returned to the known galaxy a century later…

Source: Timeline 7: Peace for the Republic?

As a practitioner of Sith Alchemy, Karness Muur is one of the most powerful Sith Lords in history:

The most powerful Sith Lords possess a talent for the dark alchemy of the Sith. The Emperor, like Naga Sadow and Exar Kun long before him, became a master of manipulating the genetic building blocks of living creatures through the dark side.

Source: The Dark Side Sourcebook

Upon merely sensing the Muur talisman's power, Darth Vader considers the possibility of being able to overthrow Emperor Palpatine using his and Muur's combined power. He also seems to regard Muur's as superior to his and even comparable to that of Palpatine's, as he believes that killing Palpatine with Muur's help would be "trading one master for another":

While Celeste Morne lacks the power to stop Darth Vader, Karness Muur does, proving his superior power over both:

Muur's power is unlike anything Vader has ever seen before:

The biggest Star Wars story of 2008 comes to the era of the Empire as Darth Vader's pursuit of power releases a force unlike any he's ever witnessed!

Source: Dark Times 11: Vector: Part 5 (Publisher's Summary)

Muur claims to have easily slain Sith more powerful than Darth Krayt as of Had Abbadon:

Muur is possibly the most powerful Sith Lord in the galaxy as of the Battle of Had Abbadon, potentially usurping the title from Darth Krayt:

But Emperor Krayt might no longer be the most powerful Sith lord in the galaxy. Will Cade and Celeste have another Sith to defeat... or join?

Source: Legacy 31: Vector: Part 12 (Publisher's Summary)

As of the Battle of Had Abbadon, Karness Muur's power is greater than that of either Cade Skywalker's or Darth Krayt's, confirming Muur is the most powerful Sith Lord in the galaxy at the time:

On Had Abbadon, in the Deep Core, Krayt confronted Skywalker a second time. But a third Force-user possessed powers that outshone them both. Karness Muur, an ancient Sith spirit, blasted Krayt with overpowering energy, sending him over a cliff to the rocks below.

Source: Insider #113: Profile: Darth Krayt

Sith Sorcery

Sith Sorcery or Sith Magic is a Force-oriented practice that involves a wide spectrum of arcane and esoteric powers.

Darth Andeddu, who possessed a large library of Sith knowledge and was renowned for his knowledge of Essence Transfer, built his knowledge on Karness Muur's experiments:

By tapping into the power of the Muur Talisman, Celeste Morne is able to turn Vader's army of clones into rakghouls:

Muur controls his rakghouls to attack everybody else on Had Abbadon:

Sith Alchemy

Sith Alchemy is a Force-oriented practice allowing one to alter physical (and sometimes Force-related) features of living beings.

Like the other Sith Lords of his time, Muur was a master of Sith Alchemy, twisting life around him. He was even involved in the creation of Leviathans, and he is seen invoking them in a flashback:

Muur created rakghouls, but when he discovered that his rakghoul plague was unable to affect Force-sensitives, he used Alchemy to alter his rakghouls so that their bite could transmit a virus that turned others, even Force-sensitives, into rakghouls:

The rakghouls' ability to transmit the virus through bite and its ability to affect Force users has been shown through the Vector series:

Dark Side Healing

Dark Side Healing is a spectrum of healing-based powers that were derived from dark side alchemy. These powers were considered rare and were highly valued because the dark side was naturally associated with corruption and decay of the body.

Muur is said to know dark side healing:

Muur claims he delved into the arts of dark side healing in life:

To prove that he is capable of healing Krayt's condition (which nobody else could heal), Muur initiates his healing technique on Krayt, seemingly displaying Dark Transfer:

Dark Transfer

Dark Transfer is an extremely rare Force power derived from the dark side that can bring a Force user back from the brink of death or kill them by pouring immense amounts of Force energy.

In order to show Krayt proof of his ability to heal Krayt's condition, Muur initiates a healing technique which seems to be Dark Transfer (both because it is identical in artwork and because Krayt learnt how to use the technique afterwards):

Force Sense

Force Sense is a basic power allowing Force sensitives to sense their surroundings, feel determine the thoughts or feelings of others, feel ripples in the Force signifying important events of the presence of the dark side, or even the future.

Muur senses Darth Vader's strength in the Force:

Muur is able to detect that Vader has sensed the power of his talisman:

Muur senses power in Luke and Leia:

Muur senses the coral seeds in Darth Krayt's body seek to expand their domain and consume Krayt's flesh:

Telekinesis

Telekinesis is a common Force ability than affords the user the ability to alter and distort reality around them.

In Celeste Morne's body, Muur ragdolls Imperial Knight Antares Draco effortlessly, hurling him into a wall head-first which incapacitates him:

In the body of Celeste Morne, Muur uses Maelstrom to blast away all the fighters on Had Abbadon whilst electrocuting a wounded Darth Krayt and Azelyn Rae simultaneously. The people seen to be sent flying include Darth Maladi and Shado Vao, but the other combatants such as Cade Skywalker were also hurled away (Cade is seen recovering in a later page):

Darth Maladi is later seen recovering in a bacta tank, indicating that the collateral effects of Muur's Maelstrom inflicted mortal injuries to her:

Muur hurls a gravely wounded Darth Krayt off a cliff whilst electrocuting him:

Telepathy/Empathy

Telepathy is the power to sense, communicate and manipulate thoughts, whereas Empathy is the power to sense, communicate and manipulate emotions.

Karness Muur is able to override Celeste Morne's Mind Trick on Pulsipher:

Muur goads Celeste Morne into attacking Darth Vader:

Muur influences Celeste Morne into angrily assaulting Luke Skywalker:

Muur telepathically calls Shado Vao through his Talisman:

Force Lightning

Force Lightning is the ability to unleash deadly crackles of electrical energy that cause excruciating pain and weaken life.

As an Ancient Sith Lord, Karness Muur is a master of Force Lightning:

Through their focus on these elements of the Force, the Sith have developed terrifying powers, such as the ability to drain a being of its life force, or unleash their hatred as crackling bolts of energy. The Sith Emperor, history's most powerful dark side master, performed a ritual of incredible scope to consume the life energy of every being on his homeworld. Ancient Sith were also masters of these arts - Lord Naga Sadow was able to affect the stars themselves, and caused the red supergiant Primus Goluud to go nova.

Source: The Old Republic Encyclopedia

In Celeste Morne's body, Muur tortures Cade Skywalker with Force Lightning, claiming he can kill Skywalker with his Lightning:

In Celeste Morne's body, Karness Muur trades Force Lightning with Darth Krayt whilst feeding off the latter's power, slowly building up power for an enormous Force Storm. When Azlyn Rae stabs Krayt from behind, Muur unleashes a devastating Force Storm that leaves Rae nearly dead, significantly injures Krayt, and hurls him over the cliff. Muur also simultaneously hurls all the other combatants away with telekinesis, with Darth Maladi later seen recovering in a bacta tank, indicating that the collateral effects of Muur's Maelstrom inflicted mortal injuries to her:

Muur's blast of Force Lightning that sends Krayt flying off a cliff is described as "overwhelming":

Karness Muur, an ancient Sith spirit, blasted Krayt with overpowering energy, sending him over a cliff to the rocks below.

Source: Insider #113: Profile: Darth Krayt

Tutaminis

Absorption, or Tutaminis, or Negate/Absorb/Dissipate Energy, is a Force ability enabling one to absorb various forms of energy and channel it for personal use.

In Celeste Morne's body, Muur seems to catch and absorb the Lightning of both Darth Krayt and Darth Maladi in the palm of his hand whilst unleashing his own Lightning:

Force Maelstrom

Force Maelstrom is a Force power involving a Force user protecting himself with Force Shield whilst simultaneously unleashing telekinesis and Force Lightning on his foes.

In the body of Celeste Morne, Muur uses Maelstrom to blast away all the fighters on Had Abbadon whilst electrocuting a wounded Darth Krayt and Azelyn Rae simultaneously. The people seen to be sent flying include Darth Maladi and Shado Vao, but the other combatants such as Cade Skywalker were also hurled away (Cade is seen recovering in a later page):

Darth Maladi is later seen recovering in a bacta tank, indicating that the collateral effects of Muur's Maelstrom inflicted mortal injuries to her:

Force Drain

Force Drain is a Force power enabling one to siphon the life energies and/or Force powers of the target.

As an Ancient Sith Lord, Karness Muur is a master of Force Drain:

Through their focus on these elements of the Force, the Sith have developed terrifying powers, such as the ability to drain a being of its life force, or unleash their hatred as crackling bolts of energy. The Sith Emperor, history's most powerful dark side master, performed a ritual of incredible scope to consume the life energy of every being on his homeworld. Ancient Sith were also masters of these arts - Lord Naga Sadow was able to affect the stars themselves, and caused the red supergiant Primus Goluud to go nova.

Source: The Old Republic Encyclopedia

Through Celeste Morne's body, Muur siphons the Force powers of Darth Krayt and uses them for his own purposes:

Essence Transfer

Essence Transfer is a Force power enabling one to manipulate his essence or those of others, and transfer it into another body.

Muur used Essence Transfer to place his essence inside that of the Muur Talisman:

Combat Skill

Karness Muur is among the ancient Sith Lords, whom Kreia claims are vastly superior swordfighters to the Jedi and Sith of her age. Specifically, she claimed that the Exile (at the time, at least) and herself were "children playing with toys compared to the prowess of the old masters".

"If you were to face an ancient Sith Lord in combat, you would learn that we are as children playing with toys compared to the prowess of the old masters."

Source: Knights of the Old Republic II: The Sith Lords

Chris Avellone, the head writer of Knights of the Old Republic II: The Sith Lords, has confirmed that Kreia's predictions are accurate:

"Kreia is setting the stage for what we imagined KOTOR3 to be, and as we had a sense for the power that we wanted those Sith Lords to reveal, her predictions are accurate. And yes, she had a number of Sith holocrons that she had read (the ones on Telos)."

Source: http://i.imgur.com/9FkGpPb.png

Karness Muur, XoXaan and Remulus Dreypa were among the Dark Jedi who fought in the Battle of Corbos. Having survived the conflict, they must have slain a number of Jedi there, as Dreypa would later recount:

In the body of Celeste Morne, Karness Muur trades blows with Darth Krayt (who is being weakened by parasites), gracefully repelling the latter's lightsaber assault with no apparent difficulty. Much of the fight occurs off-panel, but when it ends three pages later after Celeste finally wrests control back from Muur, nobody is at a noticeable advantage (though Krayt is now the one on the defensive, as opposed to being the aggressor), indicating that Muur and Krayt were at least evenly matched. This is despite Muur being nearly seven millennia out of practice with a blade, wielding a completely unfamiliar lightsaber, and having to control the rakghouls and mentally contend with Celeste for control of her body, all at once:

The Muur Talisman

Created by Sorzus Syn, the Muur Talisman is the first of the three Great Amulets to be worn by a Sith Lord. It is the culmination of Syn's experimentation with the Heart of Graush and her alchemic mastery:

"Karness Muur requested I create this, but it shall be my triumph. My experimentation with the Heart of Graush and my alchemic mastery of raising Sithspawn will culminate in the first Great Amulet to be worn by one of the Lords of the Sith. Its power will transform the feeble-minded into braying rakghouls, whose actions are the result of the wearer's desire. It will also preserve the wearer's spirit should he fall in combat."

Source: Book of Sith: Secrets from the Dark Side

A description of the Muur Talisman from The Jedi Academy Training Manual, where it is listed as one of the most dangerous Sith Artifacts to have ever surfaced, and is capable of stopping its wearer from aging:

Xamar is able to sense the Talisman, even across an entire planet:

A wielder of the Muur Talisman is able to create and control an entire army of rakghouls:

Whilst wearing the Muur Talisman, Pulsipher gains Force powers and is able to kill a Mandalorian with Force Lightning with merely a touch:

Several Mandalorians are turned into rakghouls:

The ability to control Rakghouls is made apparent when Morne, after receiving the Muur Talisman, is able to control entire legions of rakghoul to do her bidding:

Morne is able to create rakghouls out of non-Force sensitive beings as well, such as when she turns Doctor Peturri into one:

The Muur Talisman is moved by Karness Muur's will, and it has shown the ability to move of its own accord and latch onto others:

The power of the Muur Talisman is capable of resulting in galactic turbulence:

As we plunge into the final chapters of the yearlong "Vector" crossover, the power of the Talisman threatens to shake the galaxy to its foundations!

Source: Legacy 29: Vector: Part 10 (Publisher's Summary)