I can’t believe I translated this thing, but anyway. For those who don’t know, Expiatio is the novelization of Lamento, and follows very very closely to the game’s events. It focuses on Rai’s route, but the difference here is — everything is told in Rai’s point of view, so you get to finally hear his thoughts yay! Expiatio contains a new epilogue for the route that wasn’t in the game, and this is said epilogue.
This epilogue takes place some time after Rai’s good end, and basically it’s about Rai and Konoe going back to Ransen for the andou (dark winter) festival. Beware of spoilers if you’ve yet to finish his route.