Kyogai was a Lower Moon Six of the Twelve Demon Moons, earning the nickname Drum Demon for obvious reasons. He's best known for his obsession with his own writing—a passion that got him into serious trouble early on. When some unknown demon criticized his work as boring and uninspired, pointing out that he never left his house or did anything interesting, Kyogai killed him on the spot, furious that the guy had stepped on his papers on the way out.
Things went downhill from there. At some point, Kyogai lost the ability to eat humans entirely, which was kind of a problem for a demon. Muzan showed up personally to strip him of his rank, having decided Kyogai had become useless. That's when the obsession really kicked in—Kyogai spent everything trying to claw his way back into the Twelve Demon Moons, desperate to prove himself.
His plan involved capturing a kid named Kiyoshi, the older brother of Teruko and Shoichi, purely because Kiyoshi had rare blood that Kyogai thought might restore his appetite. He dragged Kiyoshi to his place—the Drum House—but before he could actually eat him, two other demons showed up wanting the same thing. In the fight that followed, Kyogai got badly hurt, and the drum that was literally part of his body got knocked clean off his back.
Content compiled by AnimeList.moe from publicly available sources.
