The Fable 

When you're the infamous prodigy hitman known only as “Fable,” many things come easy. Being a normal person, however, isn't one of them. In fact, being told that he can't kill anyone for a while may just be the hardest job Fable’s ever taken... (Source: Kodansha USA) Note: Won the 41st Kodansha Manga Awards in the general manga category in 2017.