At first glance as a blood DK I thought these guys were just doing an incredible amount of damage but upon further inspection I determined that about 70-75% of their damage is from a skill called Thunder - [spell=128999] which does exclusively nature damage which circumvents a lot of mitigation and/or absorption effects that most tanks have. The following things will help for most tanks:
- Effulgent Primal Diamond - Effulgent Primal Diamond
- Anti-Magic Shell - Anti-Magic Shell
- Rune of Spellshattering - [spell=53342]
- Icebound Fortitude - [spell=48792]
- Barkskin - Barkskin
- Divine Shield/Protection - Divine Shield/[spell=498]
- Devotion Aura - [spell=31821]
- Shield Wall - [spell=871]
- Demoralizing Banner - [spell=114203]
- Touch of Karma - [spell=122470]
- Fortifying Brew - [spell=115203]
- Zen Meditation - [spell=115176]
This is in no way meant to be a comprehensive list but I wanted to try and save some people time having to look up useful stuff like I had to do with my Monk (Still know nothing about the class). Feel free to comment with additional things that work.
Edit: Also, for those who don't know...if the packs running around where the other related quests are turn out to be too tough for you just head south to just west of the point where the river hits the edge of the map and you'll find them in easier to manage groups.