Hell’s Paradise: Jigokuraku

One of the best assassins ever trained in the ninja hamlet of Iwagakure is Gabimaru "The Hollow." He completes every task as quickly as possible with his icy, emotionless demeanor, but his circumstances suddenly alter when he is ambushed. He thus finds himself on his client's hit list and is sought after by his former coworkers. Gabimaru doesn't want to pass away just yet because he has a wife he wants to keep safe, despite being sick of living a life as a murderer.