From Lotro-Wiki.com

Lore

It is said that when the Witch-king came to Angmar, he exerted dominion over many fell spirits of Morgoth and sent them from Angmar and Rhudaur to inhabit the Barrow-downs outside of Bree...the last bastion of the Rangers of Cardolan. In the Third Age, only the wights remain to tell of those evil days.

Objective:

Defeat 100 Wights

Rewards For Accomplishment:

Tactics and Might Bonus: Tactics and Might Bonus