Those vrykul that have gained the favor of the Lich King call themselves the Ymirjar. They inhabit a city in the center of Icecrown. We have a lot of preparations to make before we assault Icecrown Citadel, and the one that stands before us now is routing these so-called "Chosen" of the Lich King.
Go to their city, Ymirheim, and slaughter them in their home. Let there be no questions as to who the stronger combatants are here.