Mangetsu Hōzuki

is the elder brother of Suigetsu Hozuki, who is currently a member of Team Hawk. He was most likely a member of the Seven Swordsmen of the Mist, hence why Kisame recognizes Suigetsu as his brother. Even though his abilities have not been demonstrated or even mentioned, Kisame implies they're similar, but more powerful, than Suigetsu's. He, like Kisame and Zabuza, also wields a particularly large sword.