Ai

She is 15 years old and is a famous thief of Lost Precious, called Odd Eye (because of her one golden eye). Her tattoo is really a lost precious which allows her to transform to a half wolf. Furumori (Ai's Master) placed it inside her as an experiment on integrating a person and a lost precious. She was taken from her home by Furumori and lied to that her family was dead and she was born a half wolf, but she forgave him before he dies in battle with Ryuji's group.
After her story arc, she finds and returns successfully to her parents. She likes Ryuji for saving her from her thieving life and accepting her form and continues to visit him in later episodes.