Second Tecteun

Tecteun was one of the first Gallifreyans to explore other planets besides Gallifrey. She discovered the Timeless Child on a barren planet and took her back to home and raised her.

When Tecteun discovered the child's ability to regenerate, she injected herself with the genes which had been spliced from the child. She later gave her people living in the Capitol this gene so that they would be able to regenerate and become Time Lords. (TV: The Timeless Children).