"I... didn't realize I needed something." What could he need? Is there something he needs? Wait. There is. There is something Thanatos thinks he needs, but he doesn't know if it's something anyone could help him with. There's a part of him that's been missing, that he's only realized recently. Something incredibly intimate and painful but also beautiful and unforgettable.

"No, that's not exactly right. There is something I think I need, that my world needs. If I'm not on this train because I am Death Incarnate, then... maybe there's still a reason for this fate." Thanatos has to believe there's a reason because his sisters are the Three Fates. They weave the fates of all.

He sighs. Ryo probably thinks he's about to say that he needs to find a way back home to the time he left it. (Which is also true but not what he asks.) "I know your world doesn't have many gods, but does your world have a god or goddess of Life? Someone... who's the counterpart of Death?"