Boku no Tonari ni Ankoku Hakaishin ga Imasu

Seri Koyuki is a high school student who tries to avoid strange people because he knows he will just end up being the straight man to their antics. Enter Kabuto Hanadori, Koyuki's classmate who has chūnibyō (second-year middle school syndrome) and claims his eyepatch seals his god of destruction alter ego. Everything about Hanadori exudes the need for a straight man to keep him in check, and sure enough Koyuki is drawn in.
Note: Includes 5 extra chapters.