Amachi

Amachi is a medical ninja/scientist who is an accomplice of Orochimaru. He and Orochimaru terrorized the people of the Sea Country and kidnapped the citizens for their deadly experiments, including Isaribi. He orders Isaribi to attack ships, promising to return her to her normal form, but truly intending to dissect her once she is no longer of use. He also seems to know Anko as well, since she was with Orochimaru at the time. Much later, in the Sea Country arc, Yoroi and Misumi join him as bodyguards and assistants. He also summons the indestructible Umibozu in this arc. He is defeated after transforming into a Kaima, and is captured by Anko's team.