To Break the Demon Gate: Yamada Monogatori, #2

Yamada no Goji is a minor nobleman of ancient Japan who has lost everything—except a single purpose: keep a promise to the woman he loved. In order to fulfill his vow, all he has to do is fight a horde of demons and monsters, bargain with a few ghosts, outwit the sinister schemers of the emperor's court, find a way to defeat an assassin who cannot be seen, heard, or touched—and change the course of history. Fortunately, Yamada specializes in achieving the seemingly impossible, so he is sure in some way to succeed . . . if he doesn't drink himself into oblivion first.