Itachi Uchiha

LOTM - Birth of Miracle Elite
Izaya arrives in the Fortuna Castle, to tells him and other bad guys off for news about Fake Dormammu's death. However, after He and other villains ask sardonically whether Izaya should kill Tuxedo to claim the throne while feasting on a chicken that Izaya supplied to them, they unwittingly gave him an idea: He then informs them of the newly-formed plan to kill both Lovelace Family and Tera's group during the song "Be Prepared".

After he helped Izaya escape, learning that Trax is betraying Izaya Orihara to his "Deadly Master". He an Kisame like the other too, waits for their allies are killed and defeat. So they can now join Dolarhyde himself.

Meister of War
Itachi Uchiha doesn't really plan to help The Murderistic League, rather he is actually on the side of good and is willingly to do what it takes to bring Johan Liebert's group to its downfall and end this pointless war.