A Marine butcher? I’m just fighting to live with everything I’ve got.

Renn Hawk, armed with the mysterious Justice System, rises in the ranks of the Marines through ruthless efficiency. Every criminal he executes feeds him Justice Points, instantly empowering his Haki and strength. With “Slaughter Justice” as his creed, he wipes out entire pirate crews before their wanted posters even hit circulation—drawing the attention of the Admirals themselves. Akainu, Kizaru, and Aokiji all compete to recruit him, while Sengoku struggles to keep the balance. In this world ruled by the strong, can Renn Hawk carve his path as the Marines’ deadliest weapon of justice? — Description from novelcodex.org