Sinon is very thin and has pale eyes. His light colored hair is tied back in a ponytail. In his Anima form, Sinon's arms become white wings. He is the only person seen in the series whose wings are not located on their back. His Anima markings are similar to Cooro's: a spiral with four feather-like shapes around it. They are located on the backs of his hands.
The gang meets him in Maggie Vil while participating in the battles at Maggie Coliseum. Sinon is one of the many kids who wanted to win a fight and agreed to be Magdala's friend in order to obtain his desire. Somewhere along the way, he regretted his choice and asked to leave, but instead was locked in a dungeon with Cooro and Husky who also refused to comply with Magdala's demands.
After trying and failing to escape, Sinon became trapped in the coliseum with two large, lion-like animals. Magdala was most likely going to let them kill him. As he was on the edge of passing out, Sinon noticed white feathers floating down from the sky and looked up to see a flock of water geese flying by. He grew wings and became a +Anima there as he wished to keep his life and fly away from there.
Sinon is later seen in Nana's nightmare.