Kyojuro Rengoku (煉 (れん) 獄 (ごく) 杏 (きょう) 寿 (じゅ) 郎 (ろう) , Rengoku Kyōjurō?) was a major supporting character of Demon Slayer: Kimetsu no Yaiba and a major character in the Mugen Train Arc. He was a Demon Slayer of the Demon Slayer Corps and the late Flame Hashira (炎 (えん) 柱 (ばしら) , En Bashira?). Kyojuro was a young adult of tall stature and muscular-athletic build. He is known to be charismatic and has an air of great optimism, having an enthusiastic smile plastered on his face nearly all the time.