Sio is the younger sister of Kuma and the main antagonist in Afro Samurai: Resurrection.
In Afro Samurai: Resurrection, she convinces Kuma to attack Afro. Once she and Kuma finished him, they took the number one headband and the head of Afro's father. Sio resurrected Rokutaro. She then had him fight Afro. He defeated Afro and killed him. Kuma realizing what they had done was wrong made an attempt on killing Rokutaro. He was then decapitated. Sio tried to save him but was killed along with him. Sio liked Afro as a child, but due to the murder of her adopted family she has a resentment towards him. Sio blames Afro for the murder of her adopted family even though he was not directly linked to their death.