Agent X is probably the most psychotic agent outside FicPsych's closed ward. It is said that the Flowers are too afraid of her to let her go. She is notorious for killing Sues without reading the charges. Her partner is Agent Arya Dragon and they reside in RC 1214. She was written by insanegrrl.
She's tall and moves in a way that puts you in mind of a predatory black flamingo. That sentence alone should tell you of her idolization of the Discworld series. Her name has caused much puzzlement, but don't ask what the X stands for. (It's Xavier – her parents sort of wanted a boy.) She is committed to ridding the world of Sues, even mild ones, and has filed her teeth to points so she can tear out their throats. She is so psychotic that even when she kills Sues before she reads the charges to their twitching bodies, the Flowers are too scared to fire her, much less talk to her.
Agent X's department is unknown, but is likely to be either the Eclectic Subdivision of Advanced Species, due to Arya's power level and X's homicidal nature and hatred of Sues, or the Department of Floaters, Special Operations Division, as she was the one called in when other agents had gotten themselves into trouble.