Shun Kaidou is a classic chuunibyou—convinced he's fundamentally different from everyone else and destined for something greater. He latched onto Saiki pretty hard after noticing how isolated Saiki seemed, deciding they were meant to be friends. Saiki wasn't exactly thrilled about it, but Kaidou stuck around anyway.
The guy's obsessed with the "Dark Reunion," which he genuinely believes is some massive evil organization. Except it's not real—it's all in his head, a product of his chuunibyou delusions. He's convinced he's the only one capable of standing up to them, which tracks with his generally overconfident personality. That said, his actual abilities tell a different story: he once hid in a bathroom stall out of fear, and he can't even swim. The contradiction between his grandiose self-image and his real-world competence is pretty much his whole thing.
Content compiled by AnimeList.moe from publicly available sources.
