Birthday: October 30
Soi is a Seiryuu Celestial Warrior. Rescued by Nakago as a child, she remains his most loyal follower. Her true name is Kaen Haku, born under the Star Room. As a Celestial Warrior, Soi has Feng Shui-related powers that allow her to control lightning and induce electromagnetic fields. She is also skilled in Fhangzang and chi-raising techniques. At 19 years old, she was born in Gen, a province near the Kuto border.
Growing up in poverty, Soi was sold to a brothel as a child. When she was twelve, Nakago rescued her, and she fell deeply in love with him. Despite knowing her love was unreciprocated and that he used her to recover and heighten his chi, Soi continues to serve him faithfully and with all her abilities.
Soi usually presents herself as a formidable armored fighter who speaks like a man, hiding her kind heart and feminine nature. Although an enemy of Suzaku, she shows sympathy towards Miaka Yuuki, particularly out of jealousy towards Yui. She even admits to envying the strength of their love and reveals to Miaka that she wasn't actually assaulted by Nakago (if she had been, she would have killed Miaka). Like Tomo, she has no desire to harm Miaka but will do anything for Nakago's sake.
She meets her end during a battle between Konan and Kuto while trying to save Nakago. Soi steps between Nakago and Tasuki's sword, sacrificing herself. Nakago then carries her lifeless body until he passes from the world of the book into the Real World. In the manga, she is seen again by Nakago in "paradise," alongside his mother when he dies.
