Kenji "Oni" Tanaka, the legendary enforcer of the Ryujin-kai, left the Yakuza life behind, burying his demon under the quiet toil of a construction worker's life. He traded his blade for a hammer, his honor for a fragile peace.

But in the rain-slicked streets of Fukuoka, a new power has risen. Goro Kuno and his viper-tattooed Kenpeitai are a new breed of gangster, driven by a nihilistic greed that spits on the old codes. When Goro's war spills into the civilian world and targets the one person Kenji swore to protect—his sister, Yumi—his peace is shattered.

Pulled back into a world he no longer recognizes, Kenji must resurrect the monster he tried to kill. To save his sister from a man with no honor, he must become a demon once more. But in a city where every hand is now against him, his one-man war for redemption may be his final, bloody epitaph.