The Ultimate Assassin Is Back summary: Read manga SSS-Class Assassin's ReturnIn the chaotic world after the invasion of reality, Mo Bei, as the backbone of the human coalition,leads the team to kill the demon king who can be resurrected again and again.But in one battle the demon and the human lost their top power at the same time,the demon king mixed Mo Bei's blood with his and one day deep in the blood river regenerated a half man and half demon monster.