Boy (Heaven Sent)

A 7-year-old Gallifreyan boy was walking through Gallifrey's Drylands when the Twelfth Doctor escaped from his confession dial.

The Doctor told him: "Go to the city. Find somebody important. Tell them I’m back. Tell them, I know what they did, and I’m on my way. And if they ask you who I am, tell them I came the long way round." (TV: Heaven Sent, PROSE: A Brief History of Time Lords)

The Doctor then went to the boy's home, the barn from the Doctor's own childhood, and ate soup while the boy and other Gallifreyans watched. Rassilon then arrived to threaten the Doctor. (TV: Hell Bent, PROSE: A Brief History of Time Lords)

When the boy was older, he wrote a textbook on Time Lord history for the Academy. (PROSE: A Brief History of Time Lords)