Black Moon, Prophecy 1

Jirou Kuronuma's life has always been a big pile of garbage, and it
seems like it's going to continue that way. What he thought was his
lucky night-getting a date with a beautiful enchantress-ends with Jirou
eviscerated while staring at the jaws of a demonic seductress! Knocking
at death's door, he's saved by Levi, a twintail'd terror with a real
sadistic streak, and wakes up in a foreign land far from his home.
Indebted to his savior, he's now Levi's little servant, assisting her in
breaking the spell that has limited her black magic skills. Jirou
better start kneeling to his new master because she doesn't want a
slacker slave that's stale in the sack!