Tanjiro is a young boy with a demon sister the lowest ranked slayer with incredible speed and power (sorry tried my best)

Muzan is the demon king his disguise is often a tall man with a lean muscular build along with an unnaturally pale skin complexion that can be easily confused as being unhealthy and sickly. He has curly black hair, and sharp, almond-shaped eyes. His irises are cat-like in appearance and colored plum red. He also possesses sharp, blue nails on his hands. (ignore the voice i tried)

As the insect Hashira of the Demon Slayer corps, Shinobu is an extremely powerful and skilled Demon Slayer, however due to her petite stature, lack of physical power and her inability to completely slice off a demon's head she had to resort to her creativity to kill demons in the heat of a battle. (dont mind the pic or voice I tried)

male, blue hair, purple and blue eyes, hides the purple eye with a eyepatch and is the last phatomhive member alive. (From black butler and don't mind the voice didn't know what to put it as)