Tasmia Mallor was the latest in a long line of Shadow Champions of Talok VIII. At birth she was taken from her mother, the then-current Champion, in a bid to ensure that no single accident or attack could ever claim both of them, and saw her only seven times during her lifetime, all at solemn ceremonies in which they were forbidden to speak. As she grew up, she was raised by priests and was trained in combat and drilled in the order of her bloodline. She loved it.
Finally, one day, her mother was killed in battle and she was brought before the leaders of Talok VIII's twelve tribes - the only time they would ever congregate peacefully - before entering the Shadow Cave, where she met the spirits of her mother and the other prior Champions. After they chastised her for never wondering how her mother died, she took to heart their counsel to protect Talok VIII (but not their warning against egocentrism) and they told her to Go In Power.
On leaving the cave, she found the inhabitants of Talok VIII on their knees, waiting for a sign - which she provided when she let the Shadows loose. After that, she became the Champion, using her position to give orders to leaders and priests, all in maintenance of the Old Ways. This lasted until the ship came.
The United Planets ship came in peace, proselytising the benefits of U.P. membership. Sent to greet the "invaders," she understood none of it, and she set about dismantling the "hideous" ship and crew. Despite their best efforts, she caused an explosion that caused the ship's landing gear to collapse. After that, the priests (who had already been harbouring doubts about the "zealot") kept her drugged until UP entry negotiations were complete. Profoundly disturbed by the cultural influx and Talok's "capitulation", she was eventually "dismissed", and told to study the galaxy to "open her mind."
On their first mission, the three were attacked by four rejected Legion applicants who wanted to kill them so they could take their place in the Legion. Using her wits, combat training and darkfield, Umbra was able to defeat all four of them by herself.
As part of the Legion, she fought Mordru, and later played a key part in saving Wildfire - despite, after her initial fierce compassion, being disgusted at the thought of the forcible integration of his two original souls.
Her pride also made her falter at times; after failing to contain the fire elemental Phy'r and being knocked out early in the fight against the combined Elements of Disaster, she began to reproach herself for failing to do better. This hard-headed attitude would make her extremely volatile.
Far later, the Blight enslaved most of Earth, including all but a few of the Legionnaires. Umbra was not among these escapees. When she was freed, she began to have a mental breakdown, prompted not only by the fact of her enslavement and what she'd been forced to do, but by the fact that the Blight's touching of her mind had meant that she'd enjoyed it. Shortly thereafter, she became one of the Legionnaires lost through a space rift and catapulted into another galaxy.
There, she became harder and colder than ever in lieu of breaking down completely and showing the fear that now guided her, while the voices of her ancestors from the shadow became faint and hard to understand. Then Saturn Girl tried to telepathically calm her, and it all went wrong - a telepathic matrix over a whole planet interfered with her powers, and the result left Saturn Girl in a coma, a shadow-creature fuelled by Umbra and Saturn Girl's combined pain and fear loose on the ship - and an Umbra completely without pain or anxiety, leaving only anger and arrogant self-confidence.
She went down to the planet, where she began to fight Singularity (a Superman-like being), for whom the telepathic illusion which had caused the trouble was being maintained (to keep him from causing trouble on his race's real planet). When Ultra Boy and Monstress went down to get her, she began to fight them too. Finally, she was knocked out by Singularity while the Legion, having captured the shadow-creature and realised what it was, knocked out the illusion causing Singularity to go looking for his original planet. Then Brainiac 5 managed to restore Umbra and Saturn Girl's minds, and Umbra finally broke down in a crying heap.
After this she finally began to heal from everything that had happened to her - until, after they managed to return to UP space, her power mysteriously cut out. To find out what had happened, she finally returned to Talok VIII for the first time since her dismissal. There she found a planet completely cloaked in shadow, and a shadow which knocked her out. Shadow Maven, one of the priests who had trained her, found her and told her that after her loss in the rift, they had believed her dead and managed to empower her "distant cousin Grev" with the shadows through the use of technology, and had him cloak the planet completely, withdrawing from the United Planets.
Angry at the thought that just as she had accepted the galaxy Talok had turned away from it, she went to confront Grev. The shadow gradually leeched back to her, until she split open the suit Grev used to control the shadow - and found a withered corpse inside, as he had been unable to withstand being a conduit for the Shadow, while the suit ran on its last programmed directives. She cast the shadow-cloak from the planet, and spent some time there before returning to the Legion.
Powers and abilities
Umbra can cast darkfields preventing all light from reaching an area from outside. These can either be complete, effectively rendering useless all light sources within the area, or hollow to allow the interior to be lit. She can also solidify these fields, to use as a more direct weapon. In later issues she has been able to form her darkfield into simple shapes like blades.
Her darkfields can also contain and perhaps absorb some types of energy, such as radioactive energy. She was even able to dim the glow of the Emerald Eye .
She is also an expert hand-to-hand combatant, and can see in complete darkness (both her own and otherwise).