This quest is not available in game.
Speak with Deathguard Dillinger in Brill.
I was told Deathguard Dillinger has a job for someone like you. If you're willing to show your value to the Dark Lady's forces, then report to Dillinger immediately.
Deathguard Dillinger's post is on the west end of Brill, near the graveyard.