Shikorae is a ghoul and an associate of the Clowns, formerly belonging to Aogiri Tree.

Originally named Rio, he was an orphan raised by his older brother and kept isolated from others because of his unique abilities. After Shiki Kijima killed his brother, he slaughtered several investigators in what became known as the Jail incident. He was eventually captured by Kijima, and subjected to extensive torture while imprisoned in Cochlea.

He was among the prisoners freed from Cochlea during the Second Cochlea Raid. After the destruction of Aogiri, he joined fellow Cochlea escapee Roma Hoito.