Kala and the other residents of the Netherworld are descendants of the people of Atlantis. But not the Atlantis familiar to Namor. Pre-cataclysmic Atlantis was a powerful surface Kingdom, 20,000 years before. The city of Netheria was situated in the southern part of the continent. Netheria was threatened by tidal waves. Fearing it was going to sink, the resident scientists enclosed the city in an unbreakable but transparent dome. When the entire Atlantis sunk to the sea, Netheria followed it to the bottom of the Atlantic Ocean.
The city remained intact within the dome. The scientist discovered a way of recycling their air supply. What they had not predicted was that Netheria would continue sinking until it settled in a sub-sea cavern. It kept them effectively isolated from all other human and humanoid races from the planet. They renamed their realm a "Netherworld". In time technology advanced. Discovering electronic television probes, Netherworlders took to keeping surveillance on their surface cousins. Said surveillance lasted for centuries but they hesitated to contact the subjects of their study.
Until Kala reached the throne of the Netherworld. Young and ambitious, Kala was not content within the traditional borders of her realm. She wanted to use her armies and their advanced weaponry to conquer the surface world. But the means of transporting said invasion force escaped her. No scientist of the Netherworld had ever looked towards developing a method. Kala realized she needed outside help. She used the surveillance system to search for an "inventve genious" that could be recruited for her cause. She chose Tony Stark.
Stark was soon trapped within a crystal-like substance and transported to the Netherworld. Kala threatened him with execution if he failed to serve her well. She also threatened to cause earthquakes that would devastate the surface world unless Stark complied. He was granted use of private laboratory facilities. He actually used them to create a duplicate of his Iron Man armor. Wearing it, Tony had little trouble escaping custody. He abducted Kala and transported to her surface. He wanted to actually see the effects of atmospheric conditions of the surface on someone having spend all their life within the protective dome.
Kala grew old and weak upon exposure to the surface air. She realized Netherworlders could not actually survive on the surface. She renounced her plans of conquest. Iron Man transported her back to the safety of her realm. Within the dome she regained her youth. Grateful, she offered her hand in marriage to the hero. He declined but played matchmaker between Kala and Baxu. Baxu was the chief military commander of the Netherworld and Kala's right-hand-man. He considered her vain but was silently in love with her for some time. Stark counted on Baxu being a stabilizing influence for the young Queen.
If the two married, the marriage was short-lived. In her next appearance, Kala mentioned Baxu as deceased. The circumstances of his death have not been clarified. Unable to conquer the surface world, Kala turned her plans of territorial expansion towards the Subterranean regions. There rivals Tyrannus and Mole Man were already in conflict. At the moment Mole Man was winning and Tyrannus was in captivity. She chose to approach and seduce the victorious Mole Man. They planned on methods of unleashing molten lava on the surface world, destroying its civilizations.
But Kala betrayed Harvey. She found the handsome Tyrannus a more suitable consort for herself. She released him, only to find Tyrannus immediately turning on her. He needed no co-rulers. The trio of rulers parted ways as enemies. Harvey in particularly was heart-broken by Kala's betrayal. The two former lovers were next seen at war with each other. Since the Mole Man could easily transport his forces on the surface, Kala had to find a way to match him. She took to wearing a protective helmet when walking on the surface. Said helmet was damaged in battle. Kala was left aged and frail again.
She sought access to the Fountain of Youth used for millennia by Tyrannus. But found it drained. In this state Kala could not return to the Netherworld, nor could seek refuge elsewhere. But the Mole Man was still in love with her. He allowed her to return to his domains as an honored guest. Instead she chose him as his consort. Due to his kindness, Kala genuinely started loving him. But she soon found a downside in her dependence on him. Harvey no longer trusted her. He was secretive about his plans. Kala found herself constantly confined within her own chambers, constantly guarded.
When the Deviants waged war on the races of the Subterranea, Mole Man was forced to flee. Kala took advantage of the confusion to escape. But she planned to seek help for her consort, hoping to recruit Iron Man to their cause. She returned to the netherworld to rejuvenate herself. But her people considered her a traitor and attacked her. The Outcasts, a Subterranean group loyal to her , intervened and war was about to start. But Iron Man answered her summons and helped resolve the situation. The Netherworlders were now willing to let Kala regain her throne, impressed by her powerful forces.
She chose to leave again to rejoin the Mole Man. She would rather be old and frail with someone loving her, rather than than young and unloved. She helped the Mole Man survive the Subterranean War but was wounded herself. She was last seen tended to by the grateful Mole Man. Her subsequent activities are unknown. Mole Man has appeared several times without his consort.