Lady Omra Avrael, Warlock of Orcus

Omra Avrael was an influential noblewoman of Brynstadt and powerful worshipper of Orcus who, along with her husband Gestor Avrael, was killed by the Order of the Argent during a failed demonic ritual deep beneath Brynstadt.  
Lady Omra, by her own admission, had a cursory knowledge of magic and could perform elementary spells. This turned out to be a falsification, as it was revealed during the confrontation in the cultist lair beneath Brynstadt that Lady Omra was a warlock of Orcus with significant arcane ability.
Lady Omra was responsible for the Avrael's close relationship with Lord and Lady Bryn after the "death" of their only remaining child, Anduwar. Omra and Gestor had a similar experience with the death of their only child over a decade past, and Lady Omra used this shared trauma to effectively disarm and distract the Bryns from the machinations unfolding beneath the city.