Kenny Ackerman (ケニー・アッカーマン ) was a member of the Military Police Brigade's First Interior Squad and the captain of the Anti-Personnel Control Squad. Kenny was a vicious killer who would slit his victim's throat. He was so proficient at not getting caught that he was considered by some to be an urban legend known as Kenny the Ripper. After meeting and befriending Uri Reiss, he worked for the crown, but secretly desired the "God-like power" that the Reiss family had possessed for himself.

He was the maternal uncle of Levi Ackerman and had taught the latter as a child on how to survive the Underground.