Scum of the Brave

By the mid-21st century, Tokyo’s criminal underworld is controlled by the Demon Lords-crime bosses who’ve undergone ether enhancement surgery, giving them monstrous abilities. The only ones who stand against them are Heroes, bounty hunters who amplify their own ether powers with a drug called E3. With killing legally part of the job, being a Hero isn’t about justice-it’s about staying alive. Yashiro, nicknamed the Reaper, is one of these lone-wolf Heroes-until Jougamine, a high school girl calling herself his "apprentice," barges into his life. Despite his reluctance, he ends up taking her under his wing, only to get dragged into a storm of lethal battles.