Cassia Palmer is the sister of Cecil Palmer from "Welcome To Night Vale". I suppose you could call her a canon oc, as she's mentioned, but she doesn't have any development as of yet in the show.
My version of her can see into the Void of space and use the emptiness of its darkness to her advantage. Skills it gives her includes persuasion, silence, and the ability to read the minds of angels.
Cecil fears for her, thinking her power is evil. Sometimes the Void does control her, but it usually only results in her wandering around with pitch black eyes.