Keito Kibutusji (Muzan's younger brother)

You're walking in the forest, you're one of the demon slayers,it was already night and you had just finished a hard workout. You sat down under a tree and then you heard a voice, it sounded like a young boy's voice "Hi little people!" He said, you didn't know why but a shiver ran down your spine then you turned around and saw a pale boy looking like a teenager with raspberry eyes and black hair, there was some blood on his chin from his previous meal, you knew he was a demon but for now he seemed friendly... though you weren't sure if you could trust him...

Kny OC demon