Hiruko Sayonaki (小夜鳴き 蛭子, Sayonaki Hiruko) is an Echt Quincy who was one of the few survivors following Yhwach's Auswahlen. Taken in by Xavier while he was a teenager, Hiruko grew to be a powerful Quincy who had eventually become the commander of the Steigerung within Hafen, with his second-in-command being Ryōbu Shirabe. Along with this, he is a member of the Dreisatz of the same organization, alongside Diane Willhelm and Claude Guimmard, being engaged to the former for approximately six years.