Kyojuro Rengoku is the Flame Hashira in Demon Slayer: Kimetsu no Yaiba, the hit anime adapted from Koyoharu Gotouge's manga. His enthusiastic personality, love of food and booming delivery made his laugh and his repeated 'umai' exclamations instantly recognisable to fans, especially after the Mugen Train film. Short clips of his voice spread across anime edits, Discord soundboards and short-form video, where the laugh became shorthand for wholehearted approval, fearless optimism and enjoying something loudly and without embarrassment.