Necromantix is an undead Eladrin woman who apparently serves Vecna. She was killed by Grai in the ruined temple of Bahamut north of Drakeford, and according to Traeak returned to unlife in the Shadowfell. She was an apprentice of The Virulent Pestulence and is apparently seeking to rejoin with him now.
She is known to use Thunder Wave, Ray of Enfeeblement, and Stinking Cloud in combat; and has used Expeditious Retreat and Fey Step to escape combat (or nearly escape!) on multiple occasions.
She has also exhibited the strange ability to be healed by the self-sacrifice of her undead minions (a wisp-wraith in the one observed instance), much to the frustration of Irann who believed he had (re)slain her.