Immerseus Detailed Strategy Guide (Heroic Mode included)

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Boss Icon - Immerseus
Introduction

This guide is intended to provide a comprehensive description of the encounter with Immerseus in Siege of Orgrimmar. It is targeted at anyone who desires to understand the fight mechanics.

This guide is updated for World of Warcraft MoP 5.4.

Immerseus is the first boss in the Siege of Orgrimmar raid instance. This is an encounter that is quite simple as far as mechanics are concerned, and which will more likely test your raid's gear level.

1. General Information↑top

1.1. Health Values

Difficulty Immerseus Sha Puddle Contaminated Puddle Congealed Sha
10-man 62M 295K 316K Heroic-only
10-man Heroic 87.2M 515K 548K 1.2M
25-man 212M 632K ??? Heroic-only
25-man Heroic 267.8M 1M ??? 3.5M
LFR ???M ??? ??? Heroic-only

1.2. Enrage Timer

The fight has a 10 minute hard enrage timer and no soft enrage timer.

1.3. Raid Composition

Difficulty Tanks Healers DPS
10-man 2 2-3 5-6
10-man Heroic 2 2-3 5-6
25-man 2 5-7 16-18
25-man Heroic 2 5-7 16-18

2. Loot↑top

2.1. Armor

Item Name Armor Slot Main Stats
Hood of Swirling Senses Icon Hood of Swirling Senses (LFR, Flexible, Heroic) Cloth Head Intellect
Ichor-Dripping Shoulderpads Icon Ichor-Dripping Shoulderpads (LFR, Flexible, Heroic) Cloth Shoulders Intellect/Spirit
Bolt-Burster Grips Icon Bolt-Burster Grips (LFR, Flexible, Heroic) Cloth Hands Intellect/Spirit
Hood of Blackened Tears Icon Hood of Blackened Tears (LFR, Flexible, Heroic) Leather Head Agility
Bracers of Purified Spirit Icon Bracers of Purified Spirit (LFR, Flexible, Heroic) Leather Wrists Intellect
Salt Water Sandals Icon Salt Water Sandals (LFR, Flexible, Heroic) Leather Feet Intellect
Soul-Soaked Gloves Icon Soul-Soaked Gloves (LFR, Flexible, Heroic) Mail Hands Intellect
Puddle Punishers Icon Puddle Punishers (LFR, Flexible, Heroic) Mail Feet Agility
Greatbelt of Living Waters Icon Greatbelt of Living Waters (LFR, Flexible, Heroic) Plate Waist Intellect
Waterwalker Greatboots Icon Waterwalker Greatboots (LFR, Flexible, Heroic) Plate Feet Intellect
Chestplate of Congealed Corrosion Icon Chestplate of Congealed Corrosion (LFR, Flexible, Heroic) Plate Chest Strength
Bubble-Burst Bracers Icon Bubble-Burst Bracers (LFR, Flexible, Heroic) Plate Wrists Strength/Hit
Corruption-Rotted Gauntlets Icon Corruption-Rotted Gauntlets (LFR, Flexible, Heroic) Plate Hands Strength/Mastery
Pauldrons of Violent Eruption Icon Pauldrons of Violent Eruption (LFR, Flexible, Heroic) Plate Shoulders Strength/Parry
Bracers of Sordid Sleep Icon Bracers of Sordid Sleep (LFR, Flexible, Heroic) Plate Wrists Strength/Dodge
Treads of Unchained Hate Icon Treads of Unchained Hate (LFR, Flexible, Heroic) Plate Feet Strength/Parry

2.2. Weapons

Item Name Type Main Stats
Trident of Corrupted Waters Icon Trident of Corrupted Waters (LFR, Flexible, Heroic) Staff Agility
Encapsulated Essence of Immerseus Icon Encapsulated Essence of Immerseus (LFR, Flexible, Heroic) One-Hand Mace Strength/Dodge

2.3. Amulets, Cloaks, Rings, and Trinkets

Item Name Type Main Stats
Immerseus' Crystalline Eye Icon Immerseus' Crystalline Eye (LFR, Flexible, Heroic) Amulet Agility
Cloak of Misguided Power Icon Cloak of Misguided Power (LFR, Flexible, Heroic) Cloak Intellect/Hit
Seal of Eternal Sorrow Icon Seal of Eternal Sorrow (LFR, Flexible, Heroic) Ring Intellect/Spirit
Purified Bindings of Immerseus Icon Purified Bindings of Immerseus (LFR, Flexible, Heroic) Trinket Intellect/amplifies damage and healing

3. Overview of the Fight↑top

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.

Videos:

  • PTR Preview — a short overview of the boss, based on PTR testing, which is extremely useful for getting a rough understanding of the fight;
  • Video Guide — a video guide of the boss, based on live-realm experience.

4. Class-specific Advice↑top

On our forums, we are maintaining threads with class-specific advice for each of the fights of Siege of Orgrimmar. So, make sure to check them out, and if you have things to share, do not hesitate to contribute!

5. Preliminary Information↑top

There are a few things we need to explain before we can look at each individual phase of the fight.

5.1. 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.

5.2. 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.

There appears to be a minimum number for each type of add, meaning that even the first first Split Phase contains a few friendly adds (in addition to the large number of hostile ones). Likewise, even if you enter the last Split Phase with Immerseus being extremely low on Corruption, there will still be a handful of hostile adds.

6. Immerseus Phase↑top

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.

6.1. Abilities

During this phase, Immerseus uses several abilities against your raid.

  • Sha Bolt Icon 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 Icon 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 Icon 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 Icon 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.

6.2. Strategy

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 Icon 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 Icon Sha Bolt as soon as they appear.
  • When Immerseus casts Swirl Icon 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.

6.2.1. Positioning

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 Icon 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.

6.2.2. Handling the Abilities

Handling Sha Bolt Icon 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 Icon 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 Icon Seeping Sha.

7. Split Phase↑top

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).

7.1. Abilities

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 Icon Seeping Sha continues to function during this phase just as during the Immerseus Phase.

7.2. Strategy

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.

8. When to Use Heroism/Bloodlust/Time Warp↑top

We recommend using Heroism Icon Heroism/Bloodlust Icon Bloodlust/Time Warp Icon 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. Given Immerseus' low health, if you use Heroism/Bloodlust/Time Warp in any of the subsequent Immerseus Phases, you may well end up having the boss die before your cooldown runs out, having the rest of it go to waste while the Split Phase is starting.

9. Summing Things Up↑top

In this section, we will very briefly summarise what the players belonging to each of the three roles have to do during this fight.

9.1. Tanks

  • Tank Immerseus facing away from other raid members, and perform a tank switch (in order to handle the Corrosive Blast Icon Corrosive Blast ability).

9.2. Healers

  • Beware of the unavoidable raid-wide damage from Sha Bolt Icon 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).

9.3. DPS

  • DPS Immerseus.
  • DPS Sha Puddles, and be within 10 yards of them when they die.

9.4. Everyone

  • Avoid standing in the void zones created by Sha Bolt Icon Sha Bolt (Immerseus Phase only).
  • Beware of Swirl Icon Swirl; do not be in front of Immerseus, and avoid the moving void zones.
  • Do not enter Immerseus' hitbox.

10. Heroic Mode↑top

The Heroic mode of the Immerseus encounter is possibly the most accessible Heroic mode in the Siege of Orgrimmar, and it presents few changes from the Normal mode version.

10.1. Differences From Normal Mode

Aside from the usual increased health and damage associated with all Heroic modes, there are two key differences in the mechanics of the fight, one in each phase.

10.1.1. Immerseus Phase

Once per Immerseus Phase, the boss gains a buff called Swelling Corruption Icon Swelling Corruption (the boss will cast this spell more than once if you spend enough time in the phase, but the cooldown is so high that this is unlikely to ever happen). Swelling Corruption has an unlimited duration, and it has a certain number of stacks. Specifically, the buff has one stack for every 2 points of Corruption that the boss has. This means that the very first Swelling Corruption has 50 stacks, and then each one has fewer and fewer stacks as the fight goes on.

Every attack made against the boss removes a stack of the buff, and causes the attacker to gain a stack of a dispellable 6-second Shadow-damage DoT, and to spawn an add called Congealed Sha. The DoT's damage increases over the course of its 6-second duration, and the Congealed Sha adds do not do anything except melee their main aggro target. Swelling Corruption has no other effects, and once all of its stacks are gone, it disappears.

10.1.2. Split Phase

During the Split Phase, Immerseus gains an ability called Sha Pool Icon Sha Pool. This causes the center of the room (the area where your raid cannot go without being damaged and knocked back, and the same area where all the adds converge) to become a large void zone. Any players standing inside the void zone take a small amount of Shadow damage every second. The void zone grows slowly over the course of the Split Phase, and it also grows each time a Sha Puddle, Contaminated Puddle or Purified Puddle reaches it. As it increases in size, its damage is also increased. The void zone shrinks in size whenever it damages a raid member, and it disappears as soon as the phase ends.

10.2. Strategy

The overall strategy for the fight remains unchanged. All that your raid must do is react appropriately to the two new abilities.

10.2.1. Immerseus Phase

When Swelling Corruption Icon Swelling Corruption is cast, the resulting Congealed Shas must be killed as quickly as possible. While they are not very damaging, there are so many of them that you must have a tank pick them up so that they do not overwhelm the raid. There are two things worth mentioning here.

First of all, we advise 10-man raids to deal with the debuff in two stages. DPS players and tanks should make enough attacks to reach 2-3 stacks of the debuff (but not more than this, since the DoT damage would be very high), and then wait (stopping DPS) for the adds to spawn. After handling the adds, when players' health has stabilised, a second round of attacks can be made, which should clear all of the remaining stacks of Swelling Corruption. After the very first Swelling Corruption of the fight, when the number of stacks is highest, it is no longer necessary to do this, and it is possible to simply attack the boss normally and then deal with the resulting adds.

Given the much higher number of players in 25-man raids, it is possible to simply attack Immerseus normally even during the first Swelling Corruption of the fight.

Note that it is possible to dispel the DoT, something which can be useful in increasing the number of Swelling Corruption stacks your raid can take down in a single wave.

Second of all, you will need to come up with a means of grouping most or all of the adds up so that they can be killed more easily. The best way to do this is to have a Holy Paladin turn on Righteous Fury Icon Righteous Fury, and have a tank standing by near them. The threat generated by the Paladin's heals will draw all the adds to them, and the tank can them pick them up as soon as they are there. If you do not have access to a Holy Paladin, you will need to look for other methods offered by your raid's composition.

10.2.2. Split Phase

The easiest way to handle the Sha Pool Icon Sha Pool void zone is to have raid members with defensive cooldowns step into the void zone for a short time, at regular intervals during the Split Phase. This prevents the void zone from growing too much. The damage that it deals to players is quite low, so as long as healers are prepared for it, it should not cause problems.

Other than this, simply perform the Normal mode strategy for this phase.

11. Learning the Fight↑top

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 Icon 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.

12. Concluding Remarks↑top

This concludes our raid guide for Immerseus. We hope you have found it helpful. Please do not hesitate to post any feedback you may have on our forums.

13. Changelog↑top

  • 24 Nov. 2013: Improved the Heroic mode strategy suggestions.
  • 25 Sep. 2013: Added Heroic mode strategy.
  • 15 Sep. 2013: Added a link to the video guide.
  • 13 Sep. 2013: Made several updates after doing the fight on live realms.
    • Updated 10-man health values, and added 25-man health values.
    • Added a mention that we believe the enrage timer to be about 10 minutes.
    • Added that we believe there is a minimum number of each add type that must be active in each Split Phase, which explains why even the first Split Phase contains a few friendly adds (previously, the guide was simply stating that we do not know).
    • Added a mention that using Heroism Icon Heroism/Bloodlust Icon Bloodlust/Time Warp Icon Time Warp in the first Immerseus Phase is important because if used in any other Immerseus phases, the cooldown would probably last longer than the phase itself.
  • 29 Aug. 2013: Added Summarising Things Up section.