Amachi

Repeated tests on his own flesh let Amachi take on the Kaima form, a cross between man and fish. Transformed, he moves markedly faster and draws breath easily beneath the waves, and he can press on into a full Kaima form suited to all-out combat underwater.

Trained as a medical-nin, Amachi puts a scalpel to work and keeps a firm handle on his chakra. His altered body opens the door to water-style jutsu, including a forceful jet of water spat straight from his mouth. He can likewise call forth Umibozu, a living body of water so tough that nothing short of a strong Fire Release technique will fell it.

Together with Orochimaru, Amachi spread terror through the Land of the Sea, snatching up its people, Isaribi among them, for lethal trials meant to engineer the perfect underwater ninja. He sent Isaribi to raid ships on the false pledge that he would restore her true body, while planning all along to cut her open once she had served her purpose. He also appeared acquainted with Anko Mitarashi from the time she spent beside Orochimaru.

In time, with Yoroi Akado and Misumi Tsurugi at his side as guards and helpers, Amachi schemed to strip an incoming vessel of its gold, again bending Isaribi to his will, and he meant as well to turn his research against Orochimaru, who had shelved the underwater project once his interest waned. During the last showdown against Anko, Naruto, Ino, and Shino, he took his complete Kaima form and raised the unbreakable Umibozu. Naruto felled him by drawing on the Nine-Tails' chakra, after which Anko seized him. Cornered, he confessed he knew no cure for Isaribi and had always meant to dissect her, a revelation that so enraged Naruto that Anko had to restrain him before striking Amachi herself.