Senketsu

Senketsu (鮮血 (せんけつ) , lit. fresh blood) is a Kamui created by Isshin Matoi, who is later revealed to be Sōichirō Kiryūin, and is a major character in Kill la Kill. Appearing as a sentient sailor uniform, he was found by his creator's daughter, Ryūko Matoi, becoming her primary ally in her battle against Satsuki Kiryūin and, later, Ragyō Kiryūin and COVERS.