Stage one- NO idea she is a Time Lord until she regenerates for the first time while searching for the Doctor.
Story- Abandoned on Earth, she was cast aside by her own people, Gallifreyans, unsure as to why she was, she searches for anything that could help her figure it out.
Slightly after her journey, she discovers she has a brother, the Master, insane and completely different from who she is, they still managed to get alone
One point of constant pain for her was when she had been ten, she looked that age anyway, she came home from school to discover her parents dead. Three years afterwards, she met the Doctor for the first time, tenth regeneration, and he stuck around for a few weeks, keeping her company, telling her stories of when he was a child and of his home
Then one day, he left, leaving behind a sonic screwdriver like his own, only with a green light instead.
Abilities- She uses her own life energy to heal people. Risking her life while saving them.
Stage Two- Increased anger, she tended to get ad at the smallest things. Begins to use her life energy to stop hears and kill rather than heal.
Story- Not much to say other than she somehow began to become angry on a regular basis.
Near the middle/end of stage two, she met the 13th incarnation of the Doctor and fell in love. Her anger began to slowly diminish.
Abilities- Her eyes would flash gold/stay gold while angry. With a single touch, she could stop a heart with a wave of her life energy.
Stage Three- Kidnapped by UNIT, she was tortured to the point of near-death. Using this method, they trained her to kill the Doctor and her closest friends.
Story- After finally escaping, she found places to vanish to, she wanted to stay away from the Doctor and her friends to keep from wanting to kill them.
Abilities- She had been trained to fight both hand-to-hand and with several types of weapons, mostly knives, but she favored hand-to-hand above all.
Interesting Note- Her coat with several bigger-on-the-inside pockets had a rumor of a snake hiding in one of them. No one knew if it was true at all until now, a small snake is known to be her friend at this point in her life. An asp named George, was her only companion.
Stage Four- The 13th Doctor finally found her and managed to help her fight back her urge to kill nearly everyone she held dear. After he died in a painful encounter with the ghosts, Sonya took possession of the TARDIS and traveled on her own.
After the Doctor came back, she was startled to find out when she had tried to heal him hundreds of years prior, it had world, only it took so long as to allow his body to heal slower to prevent regeneration.
Months after he returned, Sonya received a letter from UNIT- they had been chasing her the entire time since she escaped- stating that they created a satellite based in the Medusa Cascade that would lock onto the Doctor's TARDIS once it went to travel, it would emit a destabilizing wave that would send the TARDIS flying into the void, along with anyone on board.
But she could save him, all she had to do was to go to said satellite and stop it... But at the cost of her own life.
Without telling the Doctor why, she insisted on going to pick up their close friend, Natalia and took them all to the satellite.
After finding UNIT there, they were surprised by their abrupt departure only to have the leader remind Sonya of their arrangement then vanish herself.
without explaining anything, Sonya made her way towards the center of the satellite and into the control center.
Before entering the room, she gave the Doctor her coat to distract him enough so he couldn't follow her into the room. As soon as she entered, she dead bolted the door and locked the controls to keep him out.
Finally, she explained why they were there, why she was in the room and wouldn't allow him in.
With a final good-bye, she pressed the emergency stop button and powered the satellite down, getting doused in a highly acidic solution that broke her molecules down too fast to allow for regeneration.
Stage Five- Sonya, from an alternate universe, was ripped away from her home and set down in the original Sonya's place, exactly where she stood before she had been melted.
Story- While taking a shower, Sonya suddenly found herself standing in a strange room with a locked door.
After making contact with the Doctor outside, who was riddled with grief and the beginnings of depression, she managed to get out of the room, after telling the Doctor she had been showering just before her sudden transportation, he gave her the coat he held, a letter had been tied to the snake inside and it slithered out so the Doctor could see it.
After fainting at the realization of being in space, the Doctor carried her to the TARDIS and waited for her to wake up. When she did, he told her where to find the wardrobe. After dressing, she found Sonya's room and her journal she had kept while traveling.
Once she returned to the control room, the Doctor began to hell at her and she ran out the door only to step out onto the Master's spaceships, the other Sonya had jokingly named it the Rust bucket, without the Doctor's aid in traveling, After she stepped through, the Doctor shut the door behind her and took off, leaving Sonya on the abandoned ship.
In a fit of anger, she yanked open a door next to her and stepped through onto the TARDIS. Another fight broke out between them and then she left, through the TARDIS doors once more while in flight.
Abilities- She uses her life energy to create a wormhole inside of doorways. Once her hand touches the metal of a handle, her energy spikes through it and makes a path directly to a door in whatever room she pictures in her head. The link stays active while the door is open and is broke once it's closed and her hand is no longer touching it.
(The rest can be read in
https://docwhorp.forumotion.org/t1-timelady-sonya and then in
https://docwhorp.forumotion.org/t326-the-story-behind-sonya-s-split-consciousness)