The story focuses on high school girl Nagisa Yukiai who lives in a seaside town. She has believed her grandmother's story that spirits dwell in words and they are called "kotodama" (word spirit). One day, she strays into a mini FM station that has not been used for years. As an impulse of the moment, she tries to talk like a DJ using the facility. But her voice accidentally broadcasted reaches someone she has never expected.

When Hiro Hiyorimi tries to save a beautiful young woman from certain death, he ends up a dead hero himself! However, since the drop-dead girl is Hime, daughter of the King of the Monsters, his "reward" is to come back as a not-quite-living soldier in her honor guard of horror! That means helping fight off the army of supernatural monstrosities Hime's siblings are unleashing against her in hopes of moving up the ladder of succession. And if facing off with vampires and zombies isn't bad enough, how can anyone be prepared for the REALLY weird ones, like were-sharks, pandas and killer dumplings? This sure as hell isn't the afterlife Hiro was hoping for, but the really sad part is that Hime is the good girl in all of this... or at least as close to good as you can come when you're on the wrong side of the gates of hell!

When it comes to the fantasy MMORPG Cross Reverie, none can match the power of the Demon King Diablo. Possessing the game's rarest artifacts and an unrivaled player level, he overpowers all foolish enough to confront him. But despite his fearsome reputation, Diablo's true identity is Takuma Sakamoto, a shut-in gamer devoid of any social skills. Defeating hopeless challengers day by day, Takuma cares about nothing else but his virtual life—that is, until a summoning spell suddenly transports him to another world where he has Diablo's appearance! In this new world resembling his favorite game, Takuma is greeted by the two girls who summoned him: Rem Galeu, a petite Pantherian adventurer, and Shera L. Greenwood, a busty Elf summoner. They perform an Enslavement Ritual in an attempt to subjugate him, but the spell backfires and causes them to become his slaves instead. With the situation now becoming more awkward than ever, Takuma decides to accompany the girls in finding a way to unbind their contract while learning to adapt to his new existence as the menacing Demon King. [Written by MAL Rewrite]

Unaired anime-original OVA bundled with 12th volume of the Hitsugi no Chaika novel.