For the characters in the stories. That's what they said. Characters in different stories are disappearing so they needed someone to replace them.

( Or robots, in his case. For how long, she doesn't really know. Father Time wasn't too specific and was pretty much dodging the question when she had asked about it. )

Huh. ( So he doesn't know. Well, she's not judging. ) Good luck. No one's ever really tried to leave yet, I think.