Limited edition OVA episode of Miss Monochrome.

There was once an ogre (oni) mother who gave birth to a human looking child. Instead of an ogre's horn, this child was born with a sword in hand called the "Onikirimaru" or Ogre Slayer. He has no name and is only referred to by the name of his sword. Though he appears human, he is pure ogre. Believing that he will become human once all of his kind have vanished from the world of humans, he sets out on his destiny to slay all of his kind. Even now, in the mother world of Japan, he is still out there slaying ogres.

Makoto Kubota wandered through life, not taking things too seriously or looking too deep within himself. His job as the head of the Izumo Group's youth gang kept him pleasantly occupied with yakuza wars, mahjong and assassinations... Until the day he stumbled upon a strange drug called Wild Adapter that produces bizarre side-effects—including death. Forever changed, Kubota becomes entangled with a drifter named Minoru Tokito, and the two form an unlikely companionship that draws them deeper into the mystery of Wild Adapter...

Yuzuru was an average teenager who had almost forgotten that he was betrothed to Azusa when he was only six! Now arriving to claim what she feels is rightfully hers, only Satomi (Yuzuru's current girlfriend) stands in her way... and with the mysterious and frightening powers that Azusa brings, Satomi won't stand in her way for long!