Valdemar comes initially with two golem adds that must be tanked by different people. As you gear up this can become one person but keep it two people if you are starting out.
Throughout the fight Valdemar will spawn non-aggro constructs and aggro Enraged Elementals. Ignore the non-aggro mobs as all they do is put a temporary stone skin on the named.
The Enraged elementals will probably do more damage to your raid than Valdemar will. They hit very hard and very fast. Burn them asap. These enraged adds will spawn about every 45 seconds.
Heavy sustained dps will win this fight for you. Grab the aggro adds quickly and burn the named hard.
Valdemar only has two AOE's to contend with during the fight. One Arcane and One Trauma. Cure these before they tick the dot on you and you will be in good shape.
Good luck.
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Challenge Mode
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This name is very much the same as easy mode. When you pull the name each construct will put out three curses. This curse is just a force target on the construct that will last about 10 seconds. Cure the tank on Valdemar and cure that tank's healers.
A few seconds after pull and every 55 seconds a non-aggro 'flames of war' will spawn that puts a stoneskin on Valdemar. You will want to kill this as quickly as possible. Once the flames of war dies, three 'Enraged Flame of War' spawn and need to be burned quickly as well to allow dps on the name. When the first Enraged spawns it will place a reflect on the named so any dps performed on the named will more than likely kill you. So no DPS on Valdemar until that first enraged dies. Once that first enraged dies the reflect is gone and you can finish up the other two adds that popped.
Due to how often the stoneskin/reflect comes up it's pretty pointless to have melee dps jousting in and out on Valdemar until you have the dps to kill the adds incredibly quickly.
Keep the AoEs cured and make sure people don't get themselves killed because of the reflect.
You need to have the dps to kill all three enraged flames of war within about 45 seconds to even give you enough dps on the named to not make this an hour long fight.
Good Luck.
Updated and fixed some incorrect statements in the challenge mode version of this encounter.
Strat updated for Challenge Mode.
Also the stoneskin on the named CAN NOT be dispelled by the druid dispell.
That really is all there is. As a tank, the only thing I did even worth mentioning is us some sort of save whenever possible if I knew Divine Blast was coming. But really, it's nothing more than a 52 second cycle of killing adds and getting as much DPS on the name as you can.
We did it by putting a ranged DPS in the MT group. MT held the mob far away. MT group max range on MT. Behind the MT group we stacked up the rest of the raid in a very small area. 5 second warning on add pop.
Kill Constructs, kill adds, until you are caught up. Once you get caught up on adds, you do as much ranged DPS to name as you can after third Enraged dies. When the 5 second warning hits, everyone bunches back up as tight as possible, at range behind MT group.
We found it important to keep the raid bunch at range from the MT group due to the nasty Stuns / Stifles from the adds.
Your first kill will be a LONG fight. Ours was 35 minutes, I've heard of guilds over 50 minutes on their first kill. Power can be an issue.
Would anyone like to add more to the HM version of this named?
Hard Mode:
Non Agro pop (name stoneskins till he is dead)
Kill non agro (name reflects till first enrage is dead this is green buff)
Also once non agro dies, 3 enrage spawn about 1 second apart
You get a new non agro every 50-55 seconds off the top of my head
So basically have to kill non agro and 3 enraged in less then 50 seconds to get burn time on name, or split your DPS and just break even on non agro and enrage, as far as AoE's you can mitigate them same way you would any other hard hitting AoE's