Omerta - Kochou No Yume No Kate
Other titles :
オメルタ~胡蝶ノ夢ノ果テ~, Omerta - The End of Butterfly's Dream
Author(s) :Natsumi Kanna
The city of Tokyo is split between two mafia groups: The Dragon Head and The King Caesar organization. Due to a certain incident, the protagonist JJ, a well-known professional assassin, is framed and thus abandons his title, going into hiding — but more problems come his way.