"The Master..." She paused, trying to work out how to get through all of this. "After they regenerated, they went back to Gallifrey, sort of a way to collect themselves. Spent some time digging into the Matrix." She let out a breath. "Only they dug too far."
"The Timeless Child was a real being, a being who could never die. A child they experimented on for who knows how long, how many bodies, until they had unlocked the keys to regeneration." There was a pause. "Jack... it's me." She looked up at him, lost. "I'm the Timeless Child."