Combatants Will Be Dispatched!, Vol. 6 (light novel) — Natsume Akatsuki

While Six is attending to the urgent business of peeking up the skirt of his (male) former mortal enemy, he gets a request from Grimm to help her prepare for the upcoming Undead Festival, where spirits of the departed actually return to the land of the living. Is it fifinally this useless archbishop's time to shine?! It may have to be, as Six soon gets sidelined with new orders from Kisaragi-to construct a new, properly fortifified base for the evil organization to stage its invasion from. But since he doesn't have nearly enough Evil Points to accomplish that, he'll have to resort to his most heinous measures yet...