When you first get into Ost Dunhoth, you have a choice of going left or right. To the left is the Wound Wing, which opens up the way to the Fear Wing when completed. If you hang a right and then another right, you reach the Disease Wing (which opens up the way to the Poison Wing when completed... but more on that later). Strangely, there seems to be much less disease here than one encounters in the Lost Temple in the Trollshaws, and there are practically no wights at all. Nevertheless, Gortheron has set up a nasty, challenging fight in the corrupted gardens.
The fights here are challenging and interesting. For the groups of mobs before the boss fight, the damage type is largely acid, but there are some nasty diseases to watch out for also.
BUGS AND KERGRIM
To get to the boss fight, you must first pass through an
infestation of very nasty vermin - tank-armored gredbyg, enraged
kergrim, gravid grodbog queens and giant-sized glow-worms. There are 3
groups of various sizes and compositions, but there are some
fundamentals that hold true for all three groups:
- All of the mobs come pre-marked
- Need at least 1 tank and 1 off-tank
- Typically want to focus on single-target DPS, because...
- Crowd-control (CC) is a challenge. Mobs are either entirely immune or require extra attention from CC.
The lumbering-tank beetles are slow, damage-resistant, hard-hitting and kite-able. The kergrim are simply pissed off.
Some of the mobs here (specifically, the kergrim) feature a new mechanic that makes CC more challenging: the anger buff. When first encountered, this buff appears as a shield of red glowing shapes orbiting around the creature. This buff can be dispelled with CC attacks - roots and mezzes - but negates the first CC attempt. In order to keep angered mobs locked down, you need to do a CC "double-tap": hit with one CC skill, then another immediately after.
With the kergrim specifically, the best strategy seems to be a Lore-master hitting with Herb-lore first to break the anger buff, then with Blinding Flash for the mezz. Technically speaking, this process could be reversed (Blinding Flash, then Herb-lore), but a rooted kergrim can still attack, and since they have brutal frontal-area-effect attacks, you want to prevent them from doing so.
Group number one contains 3 Grodbog Deep-Workers (54,348 morale each on Tier II difficulty), and 2 Moria Bone-gnawers (AKA kergrim; 108,696 morale each). The gredbyg are immune to CC and have a massive armor buff, but they are slow-moving - at least, until they start getting attacked. The longer they are in combat geting beat up, the weaker their shell gets and the faster they can move. The kergrim have the anger buff, are fast and hit very hard with frontal-area-effect attacks.
The strategy here is to have one tank kite the beetles and have a Lore-master (or, better yet, two Lore-masters) lock down the kergrim with "double-tap" CC, burning one beetle at a time and then the kergrim last. Alternately, if there is only one Lore-master (or otherwise limited CC) in the raid, kill the kergrim first and have the tank keep kiting the beetles until the kergrim are both dead. Either way, the raid will want to be fairly spread out for this fight and squishies will want to keep their distance from the kergrims' frontal attacks. Keeping the mobs spread out also prevents overzealous Champions from accidentally breaking CC with area-effect attacks.
When the queens attack, keep an eye out for yellow "bomb" symbols over your head and use a Lhinestad potion immediately. This battlefield tends to get very crowded otherwise.
Group two consists of 1 Grodbog Deep-worker, 2 Deep-worm Scavengers (21,966 morale), and 2 Grodbog Queens. The worms have a range acid-spit attack and are generally a nuisance, but less of a threat than the queens or the cement-truck beetles. The queens summon swarms of adds (Grodbog Spawn, 6,624 morale) in small groups. If the spawn adds are allowed to build up, they can reach ridiculous and lethal numbers, and when they gang up on a member of the raid, they hit incredibly hard, tearing through softer targets in seconds. These spawn occur when players neglect to remove the "bomb" disease in time - similar to the wipe-causing group-stun wound that occurs in the Wound Wing - so be sure to pot any disease off as soon as you see it.
The strategy for this fight is for a tank to kite the beetle while DPS focuses on one queen at a time, killing the worms and spawn between the two queens. Lore-masters can keep themselves busy here watching out for diseases on their fellows and removing them quickly to keep the spawn population under control.
Group three consists of 2 kergrim, 2 queens and 2 worms. For this fight, use the "double-tap" CC method on the kergrim and kill one of the queens first. When the first queen is down, mop up the spawn and the worms and kill the other queen, then the kergrim last. Tanks will want to focus on keeping the swarm beetles away from the healers. On a first run-through, this fight will probably be the most challenging of the three, particularly if copious numbers of gredbyg spawn are allowed to enter the fray and rip up the healers.
Gortheron showing off his zen garden and its prize giant bonsai tree, Dourbark. Note: red markings on the bark equal red sap
Once you're through the ruins and have shaken the pesticide out of your armour, you encounter the garden of Ost Dunhoth, where Gortheron is waiting to mock you and introduce you to the next challenge: Dourbark and Baleleaf, corrupted huorns with entwined roots and a shared bad attitude. Like any good boss fight with 2 bosses at one time, the goal here is to kill them both within seconds of one another. But there are 2 other important parts to this particular challenge.
Firstly, there's the matter of the sap. As soon as you attack one of the trees, you are coated with that tree's sap, and the edges of your screen will turn the appropriate colour (red for Dourbark, white for Baleleaf). If you switch to the other tree while coated with the sap of your first tree, you change saps and fail the challenge for the group. And while you are coated with one tree's sap, attacking the lurkers it summons forth to protect it is hazardous - hitting a bog-lurker with the same sap color will ding you for 25% of your maximum morale. 4 such hits and you die. You must only attack the lurkers belonging to the other tree, so if you have red sap, hit only the white bog-lurkers, and vice-versa.
Secondly, the adds come in timed waves. Once the trees activate, you have only 1 - 2 minutes to do as much damage as possible, at which point it throws up a shield and summons forth the bog-lurkers. Once the lurkers are all dead, the tree becomes attackable again for a limited time. To beat the challenge, you must face no more than 3 waves.
The raid will need to be split into 2 roughly even teams - this shouldn't be a problem because that's how the thing works anyway, 2 teams of 6. In this case, however, the DPS for each group needs to be pretty much dead even. If one side is doing significantly more damage than the other, it may be impossible to meet the requirement of killing both trees within seconds of one another without changing sap colors.
Fire damage does well here, so Hunters and Wardens will want to use Fire Oil for their ranged attacks, and DPS-spec Rune-keepers may want to spec for fire rather than lightning. If both groups have Captains, the Captains will want to trait for Oathbreakers, and Burglars may want to equip the trait that increases the incoming damage modifier for Reveal Weakness to 12%. Damaging the trees during those phases will be something like a controlled frenzy - you want to do as much damage as possible to your tree, but not so much that the other team can't keep up with it. During each stage, you want to be able to take 25 - 30% of the trees' morale - roughly 60,000 for each attackable stage, with the remainder to be burned down after the 3rd wave of adds.
Baleleaf and some of the bog-lurker guardians. Note: white markings on the tree equals white sap - don't hit those white bog-lurkers.
There are a few different ways to handle the adds when they come in. Ideally, you want a tough tank to wrangle the adds from the opposite tree over to your side of the room - bring the white-coloured lurkers to the red tree, and the red-coloured lurkers to the white tree - but this is easier said than done. A Guardian's Challenge may inadvertently hit wrong-color bog lurkers and the Guardian will be unable to drop them for a few seconds. One method of dealing with this is to have the Guardians charge to the opposite tree as soon as the text billboards come up announcing the summoning, and move all melee attackers away from the trees to give the Guardians some manouevering room. Some groups may prefer to leave their tank parked at the other tree the whole time, but since that person can't contribute to DPS on the tree while he is standing on the other side of the room, this is only really advisable for very high-DPS groups.
The bog-lurkers come 3 at a time for each side, are colour-coded to match the trees they protect, and they hit pretty hard. If you fall and are revived during one of these stages, you will need to immediately attack your group's tree before hitting the bog-lurkers to get coated with the proper sap. If you attack a bog-lurker with no sap, it's the same thing as attacking with the wrong sap - everyone fails the challenge.
The waves of adds get progressively more difficult each time, and their behaviour changes after the first wave. For the first wave, you can simply burn the bog-lurkers one at a time until they are all dead. For the 2nd and each cosecutive wave, you will want to switch things up: burn each one down low - 3 - 5000 morale or so - and then switch targets, burning all of them down evenly and then dispatching them all more or less simultaneously. This part of the fight is not a race - Hunters can switch to Precision or Endurance to conserve power and reduce the likelihood of grabbing aggro from the tank. If one of the lurkers is killed prematurely, it will spawn another one to replace it, and keep respawning them indefinitely until all of them die at more or less the same time (within a few seconds of one another), which switches the trees back to attackable mode.
Additionally, both groups will want to take down their adds at the same time. This requires coordination and good communication. When Group A kills all their adds, Group B's tree becomes vulnerable to attack. If Group B is still fighting adds, Group A is unable to damage their tree until Group B's adds are dead, and Group B is missing out on critical seconds during which they can be doing damage to their tree. Both groups want to be focused on the same tasks at the same time, either attacking the trees or killing the adds.
To achieve this, each group will pick a main DPS target assistant, and the group will target their attacks through that person. The main DPS target assistant will focus single-target fire on each add, one at a time, burning them all down to around 3-5000 morale (enough that lingering damage-over-time effects and stray, accidental area-effect attacks won't outright kill them), then switch to a fresh target. After the initial softening, give them a second scrubbing and bring them down to 2000 morale or less, just enough that a few area-effect attacks will kill them all quickly, stop DPS and make sure both groups are caught up to one another. When all six bog-lurkers are at or around the 2000-morale mark, wipe them out with area-effect attacks and get back on the trees.
If the raid has two Captains, it may be wise to hold back on finishing off the lurkers until Oathbreakers is cooled down before renewing the assault on the trees. If the group has high DPS, this may not be necessary.
The third wave is likely to be the most difficult; healers will have burned through most of their big tricks during the 2nd wave, and a lot of skills will be on cooldown. And if the trees are not killed after the 3rd wave, the 4th wave will likely be too strong to handle because everyone will be out of gas. This is one of those cases where doing the challenge (at least this part of it) is actually easier than not doing it.
After taking down the infected trees, the way to the Poison Wing opens up. But before you head there, be sure to loot the big chest for the armour coin and a chance at a Symbol of the Elder King. These are the kinds of things you're going to be needing before long - Ivar is not far off, and then there's the final showdown with Gortheron yet to come...