Flame of Recca
The Princess and the Ninja - Awakening of the Power!! (1x1)
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A boy named Recca Hanibishi is obsessed with being a ninja. After an accident, a girl named Yanagi Sakoshita heals him, and he declares her to be his princess, and pledges to be her loyal ninja. After an encounter with Kage Hōshi, he learns that he has the ability to control fire.