Character: nikola orsinov
Nikola Orsinov is the primary antagonist of season 3 of The Magnus Archives. She is an avatar of The Stranger, an eldritch entity representing the fear of the uncanny. Notable actions include kidnapping and torturing series protagonist Jonathan Sims. Her form is that of an animate plastic mannequin.
As her source material is audio-only, Nikola has no canonical appearance, so accurate tagging may have to depend on word of the author.
In series lore Nikola's original identity was Joseph Grimaldi (a real world actor and comedian), making her a trans woman.