Amalgam Hound: Sousakyoku Keijibu Tokusouhan

Theo, a young investigator, crosses paths with Eleven, an amalgam perfectly mimicking the form of a girl. In a strange twist of fate, the two become partners on a special mission to track down other amalgams on the run after the war. However, Eleven only looks like a young girl. She's a living weapon who doesn't understand what it means to be human. Theo has no love for amalgams, but he'll have to deal with it, because a terrorist attack has rocked the nation to its core…and someone needs to get to the bottom of it!

(Source: Yen Press)