Kyojuro Rengoku is 20 years old. He has striking, fiery yellow hair that flares out into flame-like red streaks, paired with large, distinct golden and red eyes with white pupils. He also has thick, forked black eyebrows. He is tall and possesses a lean, highly athletic, and muscular build. He wears a standard brown Demon Slayer uniform, over which he drapes a distinctive white cape that fades into a yellow-orange gradient with jagged, red, flame-like ridges at the hem. He is constantly upbeat, often speaking loudly and excitedly. His famous catchphrase "Umai!" (Delicious!) when eating perfectly encapsulates his cheerful and spirited personality. Instilled by his mother at a young age, he firmly believes that those who are born strong have an absolute duty to protect the weak. Even in the face of despair or daunting challenges, he encourages others to "set your hearts ablaze," refusing to give in to negativity or bitterness.