Kamichama Karin

The Rival is Prince Kazune (1x18)

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Kazune gets jealous at Michii because he kisses Karin, so they don't talk to each other. Karin's class decides to do a play for the school festival. The script is a warped version of Snow White starring Karin as the poison-apple-princess, Kazune as an evil prince, and Micchi as another prince.