. Trained from childhood to be an emotionless, unstoppable killer, Raizo eventually rebels after witnessing the cold-blooded execution of his friend, Kiriko, who tried to escape the clan's grip.

The story is elegantly straightforward. Raizo (Rain) is a orphan trained from childhood by the Ozunu Clan, a secret society of assassins who treat pain as a path to power. After witnessing the brutal murder of his only friend, Raizo flees the clan and goes rogue.