For this achievement you need to kill 4 bosses in Utgarde Pinnacle, explanations below.
Svala Sorrowgrave
- The only big thing to watch out for is when she pulls a person onto her altar. There will be 3 adds that have to kill down, use AoE's to burst them down fast.
Gortok Palehoof
- On normal he will activate 2 adds, on heroic there will be 4 adds. Stay at max range and dps away.
- Gortok Palehoof is a tank and spank, except for when he impales one of your party members, just call out who it is and heal through it.
- Withering Roar can stack 50 times, reducing health by 500. Make sure to remove this, ice block works well here.
Skadi the Ruthless
- Grab the adds in the gauntlet, aoe them down. Pick up 5 harpoons and start the fight.
- The real thing to watch out for here is his Whirlwind, melee needs to definitely run away from this one..
- Throws a poison spear at random party members, healers be on your toes here.
King Ymiron
- The most important thing to watch for here is when he casts Bane on himself, during this time do not dps him. This can be dispelled, purged, spell stealed, etc.
- Every 20% health loss he will run to a boat and stun your party. One of the boats will AoE your group for 5,000 damage, when this happens make sure you heal up.
- One other thing to watch out for is when he summons an Orb, it does AoE shadow damage. When it is up just avoid it, it moves slow.