Lriichi/Muzan

Yoriichi (Demon Hunter, Sun Hashira, the Strongest, and the Creator of the Foundation of All Breaths)
Yoriichi has waist-length dark hair with a dark red tint and red ends. Her hair is pulled back into a high ponytail, and her bangs are like curtains. She wears long, rectangular earrings hanging down to her shoulders on a thin thread. She wears a light brown yukata and loose black pants, over which she wears a dark red haori. Yoriichi is 190 cm tall and 21 years old. She is considered emotionless because she doesn't show emotion and rarely speaks much.

Muzan (the very first demon, king and progenitor of demons, can turn other people into demons with his blood) has short, wavy black hair. Scarlet eyes with oval pupils. He wears a white shirt, tie, and a dark brown Japanese vest and trousers.
Muzan and Yoriichi were enemies; they once fought, and Yoriichi nearly won, but Muzan managed to escape. But now Muzan's greatest fear is Yoriichi.
And so, a few months later, Muzan was walking down an empty street at night (in the daytime, in the sun, all the demons burn). Suddenly, Yoriichi came out from around the corner, he somehow tracked Muzan. Yoriichi began to approach, drawing his katana from its sheath.