Yuusuke Godai is a carefree, gentle spirit, always willing to help out people. One day, he has a vision of an artifact called the Arcle, and eventually puts it on after the first of the unsealed Grongi attacks. At first, his white Growing Form is dubbed Unidentified Lifeform No. 2 by the police, and his subsequent forms are dubbed Unidentified Lifeform No. 4. As the police learns of his identity, they begin working with Godai.