This Ugly Yet Beautiful World(2004)

この醜くも美しい世界

High school student Takeru works part time as a motorbike courier. During one of his deliveries, he sees a mysterious light passing him and fall into a forest. What he had found was a girl coming out from a glowing cocoon, calling herself "Hikari." A strange monster suddenly appears attacking them, but Takeru quickly discovers he can transform into a powerful superhero.