Fell!Kkone is the Underfell Version of Kkone.
Due to Bone's yandere personality, her behaviour changes, she started to capture Kk, and treat him as a pet. When Kk didn't do her command, She will torture him immediately.
He now wears a red hoodie, still wearing their normal sweater, he have sharp teeth. And he wears a collar, He is somewhat aggressive to everyone including Bone since he is Peasant over her. He is also Barefoot.
She wears a torn sweater, The lower part of her mask was sharp, her pupils are red. She wears dark red pants and she wears shoes.