Kyojuro Rengoku 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.

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. He had long bright yellow hair with red streaks akin to flames along with two shoulder-length bangs and two chin-length bangs on the side of his head, black forked eyebrows, and golden eyes that fade to red with white pupils.

Kyojuro wore a paler brown version of the regular Demon Slayer uniform, which consisted of a brown gakuran jacket, a white belt around his waist and tattsuke-hakama pants. Over this, he wore a haori with a white -yellow gradient pattern and red flame-like ridges at the end that his father Shinjuro once worn and more than likely his father worn when they were the Flame Hashira respectively. Finally, he wore red kyahan with yellow flames erupting from the bottom-up, with pale brown tabi socks and a pair of white zōri with red straps.