Batsu'unsai Katori was a female Shinigami. She was the first Captain of the 8th Division in the Gotei 13. Over a thousand years ago, Katori became the tenth Shinigami to join the fledgling Gotei 13, making her the first Captain of the 8th Division. At one time, she was romantically involved with Seireitou Kawahiru. However, in Seireitou's account of this shared history, she only became interested in him after being rejected by Raizen Kuchiki who had taken Furuoki Ōtogawa as his lover. She later developed a hatred of Seireitou after he left her for Tsukuyo Sone. According to Yhwach, Katori was infamous for being a brutal and cold-blooded killer, which she demonstrated by massacring the Quincy of the Lichtreich when they first invaded Soul Society. Over one thousand years ago, Katori was appointed as the first captain of the 8th Division. During this time, she fought back against the Lichtreich when they invaded Soul Society by cutting the enemy soldiers to pieces with her Shikai, ultimately helping defeat the Quincy army and later settling down during the ensuing peacetime as she found things worth protecting.