Cerebro File

Sage was Xavier's first student at the institute. She found him in a cave, legs broken by Lucifer, and helped him recover. He took her back to America with him, away from the area of the Balkans, where she had to learn to fight to survive, by any means necessary. Sage was trained to be a spy, and apparently trained while the other 5 X-men wer trained to be heroes.
Under Xavier's order, she infiltrated the Hellfire club and gained the trust of Sebastian Shaw by becoming his loyal assisstant. She was to keep Xavier informed of their doings, and sometime's sway Sebastian's plans. One night, a man under the influence and control of Elias Bogan came to make a wager with Shaw. If shaw were to win, his fortune was made. If he lost, he lost Emma Frost, his White Queen. Sage influenced the game, allowing Shaw to win. Elias Bogan however, knew who had made him lose the wager, and waited with inhuman patience to strike.
Elias captured Sage and randsomed her to Sebastian for his empire. For Sebastian, the stakes were too high, and thus left Sage to get out of it on her own. The X-men, on the other hand, came to her aid and rescued her, but Bogan had left his mark. The tattooes that run on Sage's face from her eyes bear the mark of Bogan. In order to keep under the radar, she temporarily gave up her telepathic abilities, making walls that would allow no one to track or read her mind.
She later traveled with Storm's team of X-men, questing for the destiny diaries. When she had been seen as a traitor for doing something that was ultimately sabatoge of the Hellfire club, she disbanded from the group and helped Captain Britain and the New Excalibur. There, on her final mission, she was to infiltrate Alibon's league and sabatoge him from the inside out. However, something went wrong.
The personality, Diana Fox, that she had created had become her. It took over, and she had to fight her way back. She did, but not before the damage was done. New Excalibur and The Exiles were then called and transported to help Roma restore order to the Omniverse. Sage at one point was to keep an eye on Roma when she had become hurt. Roma understood that she was dying, and thus transported all of her information and beings into Sage's mind. The strain it put on Sage was much like the result of Rogue's mutation; she had to cope with numerous beings floating around in her head.
Fearing that if the information got into the wrong hands, Sage stayed with the Exiles to cope. Not only did she have these beings, but Diana Fox, whom she long thought done with, had come back and threatened to take over her body by force. In a final confrontation, Merlin emerged, trying to destroy Sage and take the information. Sage defeated him, and became one with the crystal palace
Abilities:
Computer like mind, Multitasking (in which she can use different parts of her brain at once, such as replay a movie, play solitare, and fight an opponent), Telepathy, Activation of latent mutations,and Genetic sight. She is able to learn new talents easily due to her mind.
Note:
Sage has a pressure point on her body that allows her to reboot like a computer.

Height: 5' 7"

Weight: 135 lbs

Hair: Black

Eye color: Blue

Gender: Female

Alias(es): Sage, Lady Tessa, Diana Fox, Britanna

First Appearance: X-men #132

Current Comic Book Status: One with the Crystal Palace, and waiting to be born. Elizabeth is angry.

Gaian Storyline Additions:
Sage was thrust back into the x-men when she found the Phoenix manifesting itself right before her eyes. As it usually does, a battle ensued, continued by the rebirth of Jean Grey. When Sage went into the mind of Rachel, something went wrong. She emerged believing that she was still with the Hellfire Club, and everyone walked away with more questions than they had come with. It was later found out that numerous files had been deleted from her brain, and she had to learn who she was in order to activated her back up. A trigger word, 'mole', allowed her to regain her memory, though she did still not know the source of her loss.
Later, while staying at the mansion, they were unexpectedly attacked by their own nightmares which manifested into physical attacks. Sage faced her childhood murders, seeing the part of herself she never wished to become, and watched her friends and teammates tormented before her very eyes. When she broke free, she was crying and distressed. Along with Gambit, she made her way to the foyer to find Mindee attempting to help break Jubilee out of the mirrors in her room. For a moment, Sage's barriers fluxed and allowed the personality Diana Fox to escape. Her eyes turned green and her hair blonde, while the personality emerged more hostile and violent than it ever was. She attacked the rest of the team, though everyone woke up in their own beds shortly after.
Diana Fox was not nearly done. She would emerge from the cracks in Sage's mind, when under stress or very badly hurt. Sage knew she had been witnessing 'blackouts' but did not know their source. This went on for a series of months, but just recently ended with the removal of Diana Fox.
While training Mindee in the danger room, Sage was struck, hard, and Diana Fox came out to play. She was ruthless, and rendered Mindee temporarily paralyzed for several minutes by hitting a nerve cluster in the lower back. Diana Fox wanted control of Sage's body, and attempted to get Hope Howlett to Kill Sage, or get her close enough to death, for Diana to take over permanently. The cuckoos went into Sage's mind and held the Diana Fox persona out, when they realized what Sage needed to do. It was the constant inhuman persona of Sage that had created her, and in order to destroy her, they had to combine. Sage was near fatally wounded, but emerged more mentally stable. She realized that it was Diana, shifting things around in her mind, that had triggered the relapse of believing she was Lady Tessa. Now she has to pick up the pieces, and figure out who she is.