No good deed goes unpunished, they say, and so does friendship and lowering your intensity as a human, they don't say--alas, for all his literally painful hustle and inveterate need to save others, our brave fool of a hero ends up in hell, a conception of the inferno in its full Buddhist glory, and muses (lol) if there's a return ticket.
Told in three chapters, the final part of End Tale concludes the story proper and resolves the series' panoply of ongoing mysteries: the dues of a do-gooder for relying on a power not his own, the identity of a shady transfer student, the outcome of a class president's questing abroad, and even the true name of a park.
Araragi, indeed, is the one who knows, but along the way he meets old faces, really every last one of them, who aid him on his journey for understanding, and perhaps for salvation, and you for one might not be surprised if he had another rendezvous with an erstwhile "cloistered princess" before it--guess what it is--sees an end.