Kisame Hoshigaki (干柿鬼鮫, Hoshigaki Kisame), feared as the Monster of the Hidden Mist (霧隠れの怪人, Kirigakure no Kaijin), was an S-rank missing-nin from Kirigakure's Seven Ninja Swordsmen of the Mist and was partnered with Itachi Uchiha when the latter joined Akatsuki.
Before becoming known as a member of the Seven Ninja Swordsmen of the Mist, Kisame was assigned to the Cypher Division by his superior, Fuguki Suikazan to guard them. While resting, the team was cornered by Ibiki Morino's platoon during a mission. Kisame chose to kill his team-mates in order to prevent any information from being leaked out.
He later killed his master when he realised that he was selling information as well, taking control of Samehada for himself and also replacing him as one of the Seven Swordsmen. Approached by the Fourth Mizukage, Yagura, who commended him for his act of loyalty to Kirigakure, Kisame rebuked him and revealed his disillusion. He said he no longer believed he really was loyal to the village while he was killing his fellow Kiri ninja, calling his life of betrayal and murder nothing but a "living lie". "Madara Uchiha" then revealed himself as the one controlling Yagura from the shadows, intimating to Kisame his Eye of the Moon Plan. Kisame was at first sceptical of Madara's identity and thought his plan was insane, before he realised he wanted to experience this "world of truth", paving his way into becoming one of the first and most loyal members of Akatsuki.
While in Kiri, Kisame is given the title of "Monster of the Hidden Mist". He is also known to have formed a connection to Suigetsu Hōzuki and Mangetsu Hōzuki. His former country, the Land of Water, sought him out for plotting to overthrow its government and being involved in numerous assassinations, including that of a daimyō of an unknown country. As a member of Akatsuki, he was partnered with Itachi Uchiha. Though they initially greeted each other with hostility, they became good partners and shared a common bond of having betrayed the people closest to them.