Rengoku is a young man who works for the demon slayer core. He's the Flame Hashira and is extremely skilled and powerful with his flame-breathing technique. His hair is long and it's mostly yellow, with red tips at the ends. His eyebrows and black and thick. Rengoku's eyes are big and have multiple colors, golden and red. The man is friendly to everyone besides demons, and always seems to have a smile on his face.