Nishi Yoshiyuki manga
Are you a victim of unwanted spirit possession? Is there a ghost you need sent up and away...or down to burn for all eternity? If the answer is yes, then you need Muhyo and Roji, experts in magic law. Serving justice to evil spirits is their specialty.
From Dan of Population GO: "Mutants have popped up in Tokyo. These mutants are the relatives of gods and upon consuming human blood they transform into their awakened state which resembles the god that they are related to. Hachi has a nose as good as any dog's. After his best friend is attacked by a mutant he drinks her blood in order to save her."
Hinomiya is a quiet student who never says anything, but has a supernatural power. He saved Shijiro Sayu a number of years ago when she was falling, and since then she has considered him a friend. One day, an unnatural murder occurs, and a little girl escaping the killers runs into Hinomiya and Shijiro, with the supernatural villains not far behind! -Nins Leprechaun