Carmilla Fell is the sister of Morella Fell. She was one of the actors during the Phantasmagoria and her act was known as the "The Fell Sister's Cabinet".

The performance involves her sitting across from her sister in the cabinet with a knot tied between them. The cabinet is closed and a gong is sounded. When the cabinet is opened again, the sisters switched places.

She was shown later with Albert De Blois as his protector. She also tried to warn De Blois of the danger when the floodgates protecting Beelzebub's Skull were opened.