Toshi Ryoko's sister and the youngest child of the Ryoko family. She is 7 years old. Oki is... odd and unruly. It's too soon to tell if she is afflicted with the Ryoko Family Curse that causes the women of the Ryoko family to leave unexpectedly.
Towards Oki Ryoko
Towards Toshi Ryoko
Toshi seems to be the only one in his family that attributes his sister's strange behavior as more than childhood folly.