Fūma Kotarō

Fūma Kotarō (unknown – 1603) was the adopted name of the leader of the ninja Fūma clan, which served of the Hōjō clan during the Sengoku era of Japan. He was the rival of the Assassin and fellow ninja Hattori Hanzō, whom he killed in 1596.

Reference

 * Assassin's Creed: Memories