Boku no Tonari ni Ankoku Hakaishin ga Imasu.

Seri Koyuki wants an ordinary school life, but his classmate Kabuto Hanadori insists he is a knight keeping a destructive dark god sealed behind an eyepatch. Seri knows that reacting only encourages him; unfortunately, he cannot resist pointing out how ridiculous he sounds.

Other eccentric classmates make the situation worse, turning lessons, outings, and casual conversations into grand imaginary adventures. Caught between his desire for peace and his compulsion to answer every absurd claim, Seri becomes the unwilling center of a group he keeps insisting he wants to avoid.