Kill 20 Kvaldir on the Vrykul Ledge.
This task is part of a Naz'jar Battlemaiden vision. If needed, use the Blade of the Naz'jar Battlemaiden at a time focus to return to the vision.
I know that you, like our revered lady, have unfortunate streaks of mercy that you succumb to at times. I would advise against such kindnesses this day. The Kvaldir are proud, and they will strike back if we do not cripple them completely. Kill all that you find.
Sadly, I have the inglorious task of making sure none return to the city, so you can go have all of the fun. I will cheer you on though, of course.