Yusuke's spirit beast who hatched from an egg that fed off his actions. Puu is considered to be a reflection of Yusuke's soul, likewise Puu's physical condition reflects Yusuke's, even bieng able to find Yusuke no matter where he is. This connection has caused Yusuke to think of him as his other half.

During Yusuke's second revival Puu evolved into a phoenix and protected his body from an assault from the spirit world until Yusuke's revival was complete.