Your raid should be at or above 200% Critical Mitigation to even make the AOE's manageable.
The encounter does first start with three mobs. Haldane and two trash adds. Haldane will only start with his Moderate DMG Slashing attack, Slashing Rage. This is on a 15 second recast but doesnt hit all that hard if your critical mitigation is decent.
The adds do have a frontal knockback and you will want to tank them somewhere opposite of the named. Either against a pillar in the room or against one of the walls. The adds do have a forced target that they will cast on random members of your raid so you will want to dispatch these adds fairly quickly. The forced target is an uncurable elemental.
Once your raid has dispatched the adds its time to turn your focus on Haldane. Haldane must have his confidence buff removed by priests. Haldane for the first part of this fight is pretty easy.
When you reach 67% Haldane will split into two seperate encounters and enrage. When he splits he will begin using his two other AOE's, Rage Cloud and Seething Strike. You need to make sure the two split Haldane's do not get too close together or there damage will be too great to handle.
You must tank them apart from eachother about 50 meters or so. You can't tank them too far apart because every 45 seconds or so they both port to a random scout or tank in your raid. The two mobs will also having a small mem-wipe on the port. This means this is pretty much a 4 tank fight when you are starting to learn this mob. You will have one tank on each of the named and two tanks waiting in the raid to pick up the names when they port. You will need to make sure your raid is bunched up fairly close together so that the named mobs do not port to some wierd random location amongst your raid.
Setup your raid knowing the port information. It is best to range this fight 100% to control the port locations as best as you can. Keep the Scouts between the two named at all times so the tanks can get the aggro back quickly and seperate the mobs again. Make sure your healers and mages are set apart from the scouts so when the mobs port they are not near them.
Everytime the names port they equalize their health. If your raid is under geared from the other instances you may need to ensure you keep plenty of debuffs on both of the mobs and lessen the damage. If you are fairly geared out on previous Hardmode instances you might be able to just concentrate on one of the mobs and bring both mobs health down that much quicker.
Once you get Haldane to split its pretty much a fight that is on a 45 second loop. Mob ports, tanks grab aggro and seperate, cure the two aoe's when they hit asap... mob ports again, switch tanks...ect.
The port will probably be the hardest thing to orchestrate first but once you get it down the fight is pretty easy from then on.
Good Luck!
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Challenge Mode
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This fight is no different in Challenge Mode really other than the AOE's hit alot harder and the mem-wipe seems to be a little more severe. You will need to still keep the Healer Debuff on both named for this encounter.
Keep the mobs seperated and only concentrate on burning ONE named down ASAP. The faster you burn one of them the faster the encounter ends. You only need to kill one mirror of Haldane.
Seems that Handling those mem wipes has gotten easier than before.
You need 310 crit chance for all of the HM drunder zones. There are a couple mobs I think that debuff crit chance a little bit just can't remember who they are off the top of my head.
Can anyone tell me how Crit Chance should be in HM here?
Edrickx, your crit mit and crit chance are good and seems like your raid has a good handle on the encounter. The only thing I can think of is that when you get hit with the 100k Ragecloud are you tanking the one that the rest of your raid is not on and not debuffing? Getting regular debuffs above and beyond just the class debuff will make a huge difference in how much damage the 'swap' tank will be taking. Ask your raiders to shift to the secondary Gregor on each swap for 3-5 seconds and put on 2-3 rows of debuffs.
Our raid has spent the past few weeks trying to kill this mob, we have it down perfectly in EM, and have aquired enough gear to begin fighting this mob in Challenge Mode. The mob displays 240 CB and 210 Crit Avoidence, I tank the named and have 285 Crit Mit (290 covering the 50% innate, so 5% shy of that) and 310 Crit Chance (100 over the mob's Crit Avoid).
Working the mob to 66% and having it split is no problem, the entire raid survives fine. At the split we are getting the debuffs in on the names and splitting them and start working them just fine. Randomly Ragecloud will go off and instead of hitting me for 20k or so like all the others I am getting hit for 85-100K non critical hit, and that is through 15-20k wards. I know it is an elemental hit, and I have 4.5k elemental resist. As I go down I can check both mobs and neither have their buff, so I don't think it's a debuffing issue.
is this intended? 120K elemental hits with 18 seconds in between and no clarification as to which one is going to 1 shot me.