The Left Hand of the Thaddian Minister of one of the most prominent covens, present in Grovalle, Tanwen is a sabbatical abomination - a being created by such monstrous means that it needs to be purified via fire before it can be considered 'complete'. Resembling the oracle of the Two Goddesses the Coven worships, Tanwen is of a limited mind, usually only repeating certain phrases, though usually understands ongoing situations despite her blank and unreactive nature.

Her job as Left Hand requires her to oversee all magical rituals, keep up the health of the Coven and most importantly, choosing who can join and cannot join the coven. Tanwen's motivations are unclear, for the most part, as she can seem almost robotic and emotionless at times.