Hair, eye color and haircut vary depending on what appearance she feel like giving herself. In all her forms she's a tall, shapely caucasian beauty. Her true form has pale white, almost green-tinged skin and white hair made of flower and leaves.
She is an alraune, a vampiric familiar created from a plant by Oliviero Scully Calaveras. Exist to provide him a backup haven in Worterburgh but has since gone rogue. Calla work at the Secret Valley under the stage name Ruby Diamond. Since she doesn't require sleep or any nourishment (at least, not nourishment as humans do…), she's started to look for other jobs and has plans to become either a model or an high class escort or even both.