Immerseus Guide (Immer's alt)
3. Overview of the Fighttop
The Immerseus encounter has two phases that alternate until the boss dies.
Immerseus has a Corruption resource bar, which starts out at 100 at the beginning of the fight, and which then decreases progressively as the fight goes on, based on actions performed by your raid. Immerseus dies when his Corruption level reaches 0.
The Immerseus Phase is the phase in which the fight starts and it consists in fighting against Immerseus himself, who is stationary in the center of a circular arena. When Immerseus reaches 0% health (something that will happen quite quickly, since he has a small health pool), he will split into many adds, and this will trigger the second phase.
The Split Phase starts when Immerseus reaches 0% health. The boss splits into many small adds (some friendly, some hostile) which then slowly move towards the center of the arena. The friendly adds can be healed, and the hostile ones can be damaged and killed. When all the adds have been accounted for (having been healed, killed, or having reached Immerseus), the Split Phase will end, and the Immerseus Phase will re-start.
Each add killed or healed during the Split Phase removes 1 point of Corruption from the boss, and when the Immerseus Phase restarts, the health percentage of the boss will be equal to his Corruption level. The implications of this are twofold:
You need to bring the boss to 0 Corruption to kill him.
The Immerseus Phase will be shorter and shorter as the fight goes on.
We have released a video preview of this encounter, based on our testing on the PTR. While brief, this video can give you a good idea of what to expect from the fight. We will release a full-length video guide as soon as we have done the fight on live servers.
4. Preliminary Informationtop
There are a few things we need to explain before we can look at each individual phase of the fight.
4.1. The Room
The arena where you fight Immerseus is a large circular room. Immerseus is located in the center, where he is stationary. This central area, where Immerseus is located, is covered in water, and, as we will see later on, players cannot stand in this central area (they get damaged and knocked back).
7 streams of water divide the room into 7 sectors. This division is purely visual, however, having no mechanical ramifications whatsoever. Players can walk over these streams of water freely.
4.2. Adds and Corruption Level
Regarding mechanics, we would like to present to you the way in which the boss' Corruption resource works, and how this interacts with the adds throughout the fight.
As we mentioned before, the boss has a Corruption bar that starts at 100. At the start of each Immerseus Phase (except for the first one), the boss' Corruption will be lower, depending on how many adds have been successfully dealt with. Each add that is healed or killed, respectively, will remove 1 point of Corruption from Immerseus.
Additionally, the composition of the add set-up depends on Immerseus' Corruption level. At the start of each Split Phase, one hostile add will spawn for every 4 points of Corruption, and one friendly add will spawn for each 4 points of Corruption that has been removed. For example, when Immerseus enters the Split Phase with 76 Corruption, there will be 19 hostile adds and 6 friendly adds. The upshot of this is that, as the fight progresses, there will be more and more healing adds, and fewer and fewer hostile adds. For reasons we are not yet very clear on, the first Split Phase contains a few friendly adds as well as a large number of hostile ones (when, according to the rules we have just expressed, there should be zero friendly adds), but this is a point we will clarify as soon as we have more information.
5. Immerseus Phasetop
During the Immerseus Phase, the boss is stationary in the center of his room, and he must be tanked. This phase ends when Immerseus' health reaches 0%. During the Immerseus Phase, the boss uses a number of abilities against your raid, which we will go over before discussing the strategy for this phase.
During this phase, Immerseus uses several abilities against your raid.
Sha Bolt is an ability that Immerseus uses roughly every 10 seconds. It deals moderate Shadow damage to every raid member (and to anyone within 5 yards of them), and places a small void zone at their location. These void zones persist until the end of the phase. When the phase ends, the void zones will move towards Immerseus and disappear upon reaching him.
Swirl is an ability that has two components. Immerseus will summon a number of small void zones that move around the room, dealing damage to any players who come in contact with them, and knocking these players up in the air. Immediately afterwards, Immerseus will channel a very damaging jet of water in front of him, and he will spin clockwise for 10 seconds. After the 10 seconds are up, the void zones will disappear and Immerseus will resume his usual behaviour.
Corrosive Blast is a frontal cone attack that deals Shadow damage to affected players, and debuffs them to take 300% increased Shadow damage for 45 seconds. This effect stacks. Immerseus casts this ability every 35 seconds or so. This ability requires a tank switch.
Seeping Sha is essentially a protective barrier that surrounds Immerseus (displayed as a ring of water). Players who get too close to the boss and enter this water take damage and are knocked back. This prevents players from walking through the boss, but since his hitbox is very large, it does not interfere with melee players' ability to attack.
Your raid's strategy during this phase is quite simple. We will summarise it before going into more details.
Tank Immerseus facing away from raid members, and perform a tank switch after each Corrosive Blast.
Have the entire raid spread out around the boss. Players should stay spread out at least 5 yards apart, and should always move out of the void zones caused by Sha Bolt as soon as they appear.
When Immerseus casts Swirl, make sure to avoid coming in contact with the small moving void zones. You also must make sure to avoid being hit by the jet of water that Immerseus shoots, something which may require you to move extensively depending on where you are located.
Stay out of the center of the arena, since being here damages and knocks you back.
The positioning of the raid is arguably the most important aspect of this phase. To begin with, no one except the tank currently tanking Immerseus should be located in front of him. The other tank should be close to this area in order to be able to move into position when they need to taunt (remember that you cannot run through Immerseus, only around him).
The raid must be spread out evenly around Immerseus for several reasons. First of all, this is important because over the course of the phase, there will be a very large number of Sha Bolt void zones accumulating, so you will need to make use of most of the room. Secondly, it is important to have raid members spread out at least 5-yards apart in order to avoid taking any additional damage from the nuking component of Sha Bolt. Finally, during the Split Phase, your raid will have to kill and heal adds that spawn from many positions all around the room, so it is important that raid members be already in place to deal with these adds.
It is also worth emphasizing that you will have to distribute your healers around the room in such a way that each group of players is in range of sufficient healers.
5.2.2. Handling the Abilities
Handling Sha Bolt is, by and large, handled simply by correct positioning. That said, each player will need to move regularly throughout the phase, each time a new void zone appears at their feet. Ideally, players should move only slightly outside the void zone, so that the next void zone is placed right next to it, meaning that no free space is wasted (by ending up surrounded by void zones).
Moreover, players should form such a pattern so as not to be trapped between void zones on all sides, for two reasons. Firstly, in order to avoid Immerseus' Swirl ability, you must have freedom of movement. Secondly, at the end of each Immerseus Phase, all these void zones move to the center of the arena, and you should not be in their way when they do so.
Handling Swirl itself is not something that can be planned extensively ahead of time, since the pattern of the moving void zones is not easily predictable. Players will just have to have reasonable positional awareness and to move accordingly. As for avoiding the jet of water, this simply requires that players pay attention to the facing of the boss, and move ahead of time if the jet is heading their way.
Finally, players have to stay out of Immerseus' melee range (or rather, more accurately, outside of the boss' model) in order to avoid taking damage from Seeping Sha.
6. Split Phasetop
Whenever Immerseus reaches 0% health, he splits up into a number of small adds, a combination of friendly and hostile adds, as we explained above. The phase ends when all the adds have been accounted for (having been healed or killed, respectively, or having reached Immerseus).
The friendly adds, which must be healed, are called Contaminated Puddles. The hostile adds, which must be killed, are called Sha Puddles. These adds do not do anything other than move towards the center of the room. The hostile adds do not melee, nor do they need to be tanked. They can, however, be stunned and rooted.
During this phase, you will be confronted with several mechanics.
Each time a Sha Puddle or a Contaminated Puddle reaches Immerseus, it will cause the raid to take a moderate amount of Shadow damage. Each time a Purified Puddle (a fully healed Contaminated Puddle) reaches the boss, the raid will suffer a small amount of Frost damage. To clarify, Contaminated Puddles that are fully healed do not disappear, and they continue to move towards the boss.
When a Sha Puddle is killed, all players within 10 yards of its location gain a 25% increase in damage done to Sha Puddles for a short time. This effect stacks.
When a Contaminated Puddle is fully healed, all players within 12 yards gain 25% of their mana, and gain a 75% increase in healing done for a short time. This effect stacks. It is also worth noting that Contaminated Puddles move slower the more health they have.
Finally, Seeping Sha continues to function during this phase just as during the Immerseus Phase.
The strategy for this phase is not complicated. All raid members should heal or damage the hostile adds that are in range of them (remember, your raid should be spread out evenly around the room so that all the adds can be reached). Healers will have to pay attention to the damage that the raid will take each time an add reaches the center of the room.
The most important thing to do in order to maximise your raid's performance during this phase is to make sure that DPS players are within 10 yards of dying Sha Puddles whenever possible, and that healers are within 12 yards of Contaminated Puddles that are being healed to full health, in order to benefit from the buffs that are provided in this way.
7. When to Use Heroism/Bloodlust/Time Warptop
We recommend using Heroism/ Bloodlust/ Time Warp at the start of the fight. This is mostly because there is no specific reason to use it at a later time, and benefiting from all raid members having all their cooldowns available at the start is very advantageous. Additionally, this timing is suitable since the first Immerseus Phase is the longest of the fight, and you should try to get it out of the way as quickly as possible.
8. Summing Things Uptop
In this section, we will very briefly summarise what the players belonging to each of the three roles have to do during this fight.
Tank Immerseus facing away from other raid members, and perform a tank switch (in order to handle the Corrosive Blast ability).
Beware of the unavoidable raid-wide damage from Sha Bolt (Immerseus Phases only).
Heal Contaminated Puddles, and be within 12 yards of them when they reach full health.
Beware of the unavoidable raid-wide damage that goes out each time an add reaches the center of the room (Split Phase only).
DPS Sha Puddles, and be within 10 yards of them when they die.
Avoid standing in the void zones created by Sha Bolt (Immerseus Phase only).
Beware of Swirl; do not be in front of Immerseus, and avoid the moving void zones.
Do not enter Immerseus' hitbox.
9. Learning the Fighttop
There are two crucial aspects that your raid must master in order to defeat this boss.
The first is proper positioning during the Immerseus Phases, allowing you to avoid taking any damage from Sha Bolt void zones and allowing all the adds during the Split Phase to be handled quickly and efficiently.
The second is maximising the benefits from the buffs that go out in a small radius around adds that are dying or being healed to full during the Split Phase. Having many raid members benefiting from the damage and healing buffs can make these phases go by much more smoothly.