The Time Lairde Of Gallifrey - Book One

Trapped in a darkness so vast there is no sound, one lone figure floats in a space that has no substance. A sphere brushes against their hand, and they follow it into a light, escaping the abyss of nothingness into a world where their people are no more.

The Captain must deal with the continued absence of the minds of their people, but luckily there's one left: the Doctor. One of their brothers, the only Time Lord left in existence. They struggle with adjusting back into life, traveling with the Doctor and his companion.

~
" There's a tickle in their consciousness, but otherwise their head was still empty, so empty. "Oh, they're all gone!" They cried, their voice sorrowful. Sadness swept over them. "But not you! You're still here, who are you? Where's everyone else? My brothers? Where are my brothers?"

"But you can't be, you died!" The man was still shocked, and there was a sadness mixed with disbelief in his expression.

"Can't be what?" They tilted their head and raised a brow, then got distracted by a strand of brown hair that fell across their eyes. They lifted a hand to push it away, staring at their new pale skin, a dopey grin stretching their lips.

"You can't be them!" The man continues to ramble, and they just frowned.

"I am the Captain." They watched the man's face, watched as emotions changed and switched. "I jumped into the Void to avoid getting killed by a Dalek. Well, I jumped sideways and fell into the Void." "
~

I'm bad at summaries, but basically they're the Doctor's younger sibling who was stuck in the Void after the Time War and they go with him. Starts at the end of series 2, "Army of Ghosts". Also, if you don't think there are third genders, kindly keep your opinions to yourself because I exist and the Captain identifies as a third gender as well.

Also, the casting is a bit wrong, so please bear with me until I can fix it.