Raid Encounter Guides - Omnotron Defense System (Blackwing Descent)

Video: Our recent Omnotron Defense System Heroic 25 kill. Information on the Heroic mode of this encounter is below the Normal mode abilities towards the end of this post.

Omnotron Defense System

The Omnotron Defense System is one of the first bosses you'll encounter in Blackwing Descent, and one of two bosses you will need to defeat in order to access the rest of the zone. Included in this guide are the boss abilities, strategy suggestions, and a video of our heroic mode kill and some info on the heroic mode abilities.

This fight is a council-type fight against four constructs with a shared healthpool - Magmatron, Toxitron, Arcanotron, and Electron. The constructs become active in a random order and you can face any combination at one time. You will fight against all four constructs in this encounter, however, only two constructs will be active at any given time. Spatial awareness and quick target changes are key to succeeding in this fight.

Each construct has an energy bar which starts at full when it is activated and decreases over time. At 50% energy, the construct will activate a shield specific to its abilities and become invulnerable and another construct will activate. The construct will deactivate at 0% energy and will remain inactive until reactivated by the encounter.

You can tell which construct will be activated next by a beam connecting from the forge in the back of the room to a deactivated construct. The beam will be a different colour for each construct - a red, magma-looking beam for Magmatron, a green beam for Toxitron, a purple beam for Arcanotron, and a blue lightning beam for Electron. Each construct has its own unique abilities.

Abilities (source)
Arcanotron:
-Power Generator: Summons a Power Generator under a random friendly target. This generator increases damage by 50% of all friendly and enemy targets within 5 yards. Lasts 1 minute.
-Arcane Annihilator: Inflicts significant Arcane damage to a random enemy target. 1.5 second cast time. Can be interrupted.
-Power Conversion: Power Conversion converts damage against the target to be converted into additional Magic damage and increased cast speed. Purge, Spellsteal, or stop DPS.

Electron:
-Lightning Conductor: Targets and effects a raid member for 10 seconds, causing them to inflict Nature damage to nearby allies every 2 seconds.
-Electrical Discharge: Inflicts Nature damage to up to 3 enemies within 8 yards. Damage is increased by 20% between each jump.
-Unstable Shield: Attacks against the Unstable Shield cause a Static Shock at a nearby enemy's location. Stop DPS.

Magmatron:
-Incineration Security Measure: Inflicts 14000-15000 Fire damage every second for 4 seconds to the entire raid.
-Acquiring Target: Acquiring a target. After 4 seconds Magmatron will channel his Flamethrower on a target, inflicting ~35000 Fire damage every second to all enemies in front of him for 4 seconds. The Flamethrower appears as an obvious red beam directed onto the target.
-Barrier: Absorbs 150000 damage and, if the barrier is broken, it releases a gale of flame, inflicting ~76000 Fire damage to all enemies.

Toxitron:
-Chemical Bomb: Fires a Chemical Bomb at a random target, causing a Chemical Cloud at the location. The chemical cloud doubles damage taken and can affect Constructs as well as raid members.
-Poison Protocol: The Poison Protocol creates Poison Bombs that will explode after coming in contact with its target or after being killed. Poison Bombs will Fixate on random raid members and move towards them and will explode on contact. Poison Bombs can be snared and slowed.
-Poison Soaked Shell: Applies Soaked in Poison on melee and spell attacks which inflicts 5000 Nature damage every 2 seconds. Stacks. Will increase damage done to the target, however, it will also stack and inflict damage on any raid member effected.

Strategy
You will only need 2 tanks for this fight as only 2 constructs will be active at any one time. The fight will begin with only one Construct active, the second Construct becoming active when the first reaches 50% energy. The order of the constructs is random; you could start with a different construct each pull and have the remaining constructs activate in any order and in any combination. One construct will deactivate while a new one activates, freeing the tank to pick up the new boss.

Each construct has two unique offensive abilities and a third Shield ability which activates when the specific construct hits 50% energy. Quick target switches are key in this fight due to these shields - all of the shields will result in increased damage to raid members if they are DPSd. The shields are activated when a construct's energy reaches 50% - this is also the time a new construct will activate, so it is simple to change to the newly activated construct when the shield is powering up on the previous target.

Arcanotron's Power Generator forms light-coloured puddles on the ground which increases the damage of anyone standing in them and will regenerate mana for casters. The raid should move into these puddles when they can for the damage gain, though raid members shouldn't stand in them if it puts them in danger of an ability from a different construct. These puddles will also increase the constructs' damage, so the constructs should be moved out of them. Arcane Annihilator is a hard-hitting cast which should be interrupted. It may not always one-shot people, however, it will do significant enough damage that you could easily lose raid members if they are hit by this and another ability in quick succession.

Damage to Arcanotron's shield will give a haste buff to the Annihilator cast, so it is essential that DPS switches quickly and any stacks are Purged or Spellstolen.

Electron's Lightning Conductor affects a targeted raid member and causes them to shock nearby raiders with electricity. Any raid member affected should move away from the rest of the raid. Electrical Discharge is simply a chain lightning - you may find it easiest to spread your raid out whenever Electron is active to mitigate this damage, though it is not strictly necessary. Depending on your group and the composition of the two constructs active, you may find it more useful to keep your raid stacked together for AoE heals. If stacking, people should be aware of the chain lightning and healers prepared for quick top-ups so that you don't lose raiders to a combination of chain lightning and another ability.

Damage to Electron's shield is extremely dangerous - DPS to his shield will cause Static Shock which can quickly lead to a raid wipe. This includes the tank's damage! The tank will need to stop attacking as well when that shield goes up. ETA: A good note from our Bear Reesi (of The Inconspicuous Bear), even abilities like Demoralizing Shout/Roar will trigger this shield!

Magmatron's abilities are pretty hard-hitting and unavoidable. Incineration Security Measure inflicts an AoE Fire Damage to the entire raid. There is no way to avoid it - it must be healed through. Raid-wide cooldowns may be helpful, such as Power Word: Barrier and Aura Mastery. Acquiring Target focusses a Flamethrower (a giant red beam) onto a random raid member. The targeted member must be healed through it. Other raid members should ensure they are not caught in the beam or in front of Magmatron or they will be hit as well. You can choose to have the targeted raid member run away from the group or simply have the rest of your raid shift to avoid them. Having your raid move (rather than the target) may better help prepare you for Heroic mode, which I will touch on shortly. Certain abilities can avoid Flamethrower: Cloak of Shadows, Divine Shield, Ice Block.

Magmatron's Barrier shield will inflict massive AoE damage to the entire raid if it is DPSd and broken.

Toxitron's Chemical Bomb creates a green chemical cloud on the ground, doubling damage taken by anyone stood in the cloud. This includes damage the construct takes - if you are able to carefully position an active construct in the cloud, you can increase damage done to it significantly. Toxitron also summons adds called Poison Bombs. These are non-elites which will fixate on random raid members and explode for significant damage should they reach their target. These adds can be slowed, so abilities like Frost Trap and Earthbind Totem are extremely helpful. DPS must kill these adds before they reach their targets. Melee are best off retreating to range to ensure they are a safe distance away from the adds in case they are targeted, however, if they are not fixated, they can carefully assist in DPSing the adds as well. No one should use any aggro-dropping abilities such as Feign Death if they are fixated by an add - the adds will reset aggro and fixate on another target, which could result in the add fixating on someone who happens to be right next to them.

If you position Toxitron on one side of the room and your raid on the other, this can help to funnel the adds in a specific direction, making it easier to AoE them and to ensure they pass through any Frost Traps which may be down.

Toxitron's shield is arguably the least dangerous, Poison Soaked Shell applying a stacking Nature damage debuff. The debuff can be cleansed. This debuff will actually cause people to inflict additional Nature damage with their attacks, however, it will also inflict damage on the affected raid member. If your healers feel they can handle it, you may be interested in letting a few DPS remain on Toxitron a bit longer, though it may not be worth it. You will still need to change targets to the newly activated construct eventually.

The only ability which you may find you need to spread out for is Electron's chain lightning, which can arguably be handled while stacked up anyway. This may make it easier for targeted raid members (for Lightning Conductor and Fixate) to move out of the raid or for the raid to move away from them (such as for Magmatron's Flamethrower). Stacking up when you can may be helpful for raid healing and cooldowns like Power Word: Barrier to assist in healing. This in particular can be helpful in Heroic mode.

Heroic Omnotron Defense System
In all of the Blackwing Descent heroic modes, Nefarian appears to liven things up a bit and add difficulty to the fight. In addition to regaling us with his rather, er, eccentric presence, Nefarian generally adds a type of Shadow magic to the fight, giving the bosses additional abilities.

For the Omnotron Defense System, Nefarian adds an additional ability to each construct. Nefarian's meddling is on its own cooldown separate from the constructs, so you may find yourself faced with any of the new abilities depending on which constructs are active and when his cooldown timer is up. Some of these combinations can be particularly dangerous depending on which constructs are active at the time.

Shadow Infusion: Nefarian causes Electron's Lightning Conductor target to become fused with Shadow. Causes Shadow damage to allies, inflicting damage based on the distance from the Shadow Infusion target.

The Lightning Conductor will still tick for approximately 5 seconds while the target is becoming Infused with Shadow, so the target should move out of the raid initially. Once the Lightning Conductor turns into  Shadow Infusion, though, the target must immediately re-stack with the rest of the raid (priest's Leap of Faith is excellent for whipping a target quickly back into the group) to reduce the damage. Damage from Shadow Infusion increases the farther people are from the target, so your raid must be stacked up to mitigate this damage. If a tank has to be out of the group for whatever reason, it is advisable to use external cooldowns.

Encasing Shadows: Nefarian holds Magmatron's Acquired Target in place, preventing them from moving.

This ability roots the Flamethrower target in place, preventing them from moving. This is why it's advisable to practice from normal mode always having the Flamethrower target remain in place while the rest of the raid moves to avoid the beam, so everyone is prepared should the target find themselves rooted by Nefarian.

Arcane Blowback: Nefarian fires shadows at a Power Generator pool left by Arcanotron, causing it to expand and explode, inflicting Arcane damage to anyone caught in it. (TY to Haast for pointing me to the name of this ability!)
Raid members need to be very aware of these pools when standing in them, as they can expand very rapidly when Nefarian targets one and the resulting explosion will severly injure, if not kill, anyone caught by it.

Grip of Death: Nefarian ports to the centre of a Chemical Cloud and grips the entire raid into the cloud.
This can be a particularly dangerous ability, especially if it happens to be timed with Incineration Security Measure. The raid needs to move as quickly as possible back out of the cloud. It is also extremely important that adds are slowed and killed quickly. If any adds are still up and catch their target while the raid is gripped into the Chemical Cloud, you will likely wipe.

Heroic mode makes the normal mode spatial awareness and target swap requirements even more important as any losses can be extremely costly. You may wish to run more healers than you normally would to help deal with the significant raid damage.

Ultimately this Heroic mode comes down to knowing the different boss abilities and Nefarian's meddlings - raid members need to be able to react quickly and correctly to whichever Nefarian ability is active. The fight can quickly appear to become chaotic as people lose track of which constructs are active and which Nefarian ability is likely to be next. You can begin to figure out which Nefarian ability to expect based on his timer, though - as his cooldown finishes, you can plan to expect one of two abilities based on which constructs are active. For example, if Toxitron and Arcanotron are active, you can prepare for either being gripped into a Chemical Cloud or for a Power Generator pool to blow up.

Keeping the raid stacked together can be extremely useful for ensuring as many raid members as possible benefit from AoE healing and raid cooldowns like Power Word: Barrier, which you can see used frequently for the Incineration Security Measure in my Heroic video at the beginning of this guide. Similar cooldowns such as Aura Mastery and Divine Guardian can also be extremely helpful. There is a lot of damage both on raid members and on the tanks in this fight, and you may wish to run more healers than you would use on Normal mode. DPS does need to be strong, however, as there will be a 10 minute enrage timer on the Heroic mode of this fight (effective in Patch 4.0.6).

Good luck and have fun!