Relmyna Verenim is a Dunmer sorcerer who lives in Passwall, a hamlet in The Fringe, outside the gates to the Shivering Isles. She is the creator of the Gatekeeper who guards the gates and has their keys.
She can sometimes be found in one of the rooms in The Wastrel's Purse. It is suggested that she had a relationship with Sheogorath, who helped her create the Gatekeeper. She considers the Gatekeeper her child, visiting him every night at midnight. She talks to him and cries (the Gatekeeper does not attack her). Her tears, which remain on the ground, are poisonous to the gatekeeper.
She seems to be sadistic, as well as having a very high opinion of herself. She is overly critical of her assistant, Nanette Don, constantly belittling her absentmindedness. She shows very little emotion about her "test subjects," and her home is littered with her failed experiments. In the beginning of the quest Rebuilding the Gatekeeper she is in Sanctum of Vivisection, torturing people with fire, darts, and trapdoors. It is also heavily implied that she had a rather close relationship with Sheogorath at some point prior to the Champion's arrival.
Relmyna orders the Hero to bring her four ingredients to rebuild the Gatekeeper from the Gardens of Flesh and Bone. Once they have been obtained, she performs the incantations to build the new Gatekeeper.