Hello and welcome to the Blackwing Descent Raid Guide! My name is Aliena and in this video I'll show you all you have to know about the heroic Omnotron Defense System encounter. We completed this fight with 2 tanks, 8 healers and 15 DPS, but similar raid configurations may work just as well. I'll assume that you're familiar with the normal mode of this encounter and will only explain what changed in the heroic version.
The heroic Omnotron Defense System has a combined healthpool of 165 million.
Once you enter heroic Blackwing Descent, and especially if you've already defeated a few encounters in here, you'll notice that Nefarius in his human form chimes in on every fight and meddles with the encounters to make them more challenging. On Omnotron, you'll see him shout "With so many counters to each construct's attacks, I'll have to rectify these designs for them to provide me any entertainment".
That's exactly what he does. Every 35 seconds or so throughout the whole encounter, Nef will buff a Construct's ability. Which ability he buffs depends on which constructs are currently active.
For the most part, your ranged raid members and healers will want to remain stacked in one spot. It's helpful to assign a raid marker to a reliable ranged raid member that people stack up on. You'll see why in a second when I explain the constructs' buffed abilities.
If he buffs Electron, the Lightning Conductor ability will have an ability called Shadow Infusion attached to it. After 2 ticks of Lightning Conductor, Shadow Infusion will start ticking. Unlike Lightning Conductor, which deals damage to nearby targets, Shadow Infusion deals damage to every raid member, but the further away you are from the person with Shadow Infusion, the more damage you take.
To counter this, when Nef buffs Lightning Conductor, the afflicted person should move just a tad out of the raid for the two ticks of Lightning Conductor, and then immediately move back into the raid for Shadow Conductor. Even tanks and melee DPS should be reasonably close to the ranged pile for this. If the person with the buffed Lightning Conductor does not realize that he or she has Shadow Infusion and runs far away, Lifegrip them back into the raid to avoid a wipe.
If he buffs Toxitron, he will grip every raid member into Toxitron's poison cloud. Be warned that the cloud now also deals damage when you stand in it, so every raid member needs to move out of this as soon as possible. This sometimes poses an issue when the grip happens right after Toxitron releases his slime adds. To lessen the chance of a raid member getting pulled on top of a slime and blowing up the raid, always keep ranged raid members far away from Toxitron when he's active so that slimes have a long way to run; and make sure that killing adds is utmost priority.
If he buffs Arcanotron, his Power Generator rune on the ground will turn into an unstable power generator, expand to about 4 times its original size, and then explode. Anyone remaining in the area of the unstable generator is highly likely to die. Since you want to have your whole ranged and healer team in the generator whenever it's up, everyone needs to pay close attention to their feet when Nef's ability buff is drawing close. As a sidenote, if you have Toxitron up at the same time as Arcanotron, and you're running from an exploding puddle, make sure you're running AWAY from Toxitron and not into him, to avoid having slimes spawn in your face and annihilating your raid. Preferably you want to re-locate to another power generator if it's already up, or stand in the general area of Arcanotron and wait for another one to pop.
If he buffs Magmatron, the person receiving Acquiring Target will be rooted in place. Typically, you want to have the targetted person run out of the raid so not everyone has to move for it, but when the acquired target is afflicted by Encasing Shadows, everyone near them will have to take a few steps to the side to avoid getting hit by the flame jet.
Naturally, all abilities also deal significantly more damage than they do on normal, and the buffed abilities introduce a lot of movement to the fight.
The abilities themselves aren't the problematic part, but the fact that the construct order changes everytime you pull the boss will likely result in a longer learning curve.
Some Construct combinations can be rather devastating to your raid group - for instance it is possible to have Incineration Security Measure (that's Magmatrons Fire AoE) go off basically at the same time as a Shadow Infusion. Cooldowns should be used on many if not all AoE abilities. We had a disc priest in the group to Power Word: Barrier the Shadow Infusions, and we had Aura Masteries and Divine Guardian for Incineration Security Measure.
It's incredibly important to be aware of the different construct combinations and to know what problems they can potentially pose for your raid. Some general rules to follow:
-Always have your ranged raid members and healers grouped up
-Have interrupters assigned to Arcanotron, his Arcane Annihilator basically kills people outright.
-Do not break a shield, ever. This is incredibly important on Electron. Breaking his shield will almost always result in a wipe.
-Always have your ranged pile far away from Toxitron. When no cloud is out, try to have Toxitron positioned on one side of the room while your ranged is roughly at the entrance. When a cloud spawns on them, they move into the direction away from Toxitron. This should ensure that no adds blow up.
-Any construct active at the same time as Toxitron should be positioned away from Toxi
-Always make use of Arcanotron's Power Generator but watch for it blowing up.
-When Electron is active, be ready to group up for Shadow Infusion. If Toxitron is up at the same time a Shadow Infusion happens, have him and his tank be slightly out of the group, just in case adds will spawn.
-Any mistake you make while Magmatron is out will likely kill people. Any usually avoidable damage that is taken when Incineration Security Measure goes off can kill people.
-Time your cooldowns well. Be aware of and ready for high raid damage abilities.
-If you're tanking Arcanotron, pull him out of the Power Generator as soon as it spawns or you will get 2 shot.
That about sums up heroic Omnotron. I've attached footage of the whole encounter in case you were curious about how we handled the various mechanics in detail.
One thing that was missed about this encounter which is incredibly important to take into account is that his energy drops significantly faster on heroic mode.
Each construct uses their abilities at relatively static times according to their energy. This results in their abilities being used much more frequently than in normal mode. So not only are you getting used to Nefarian buffing the abilities that are out, but it's also normal mode on hyper speed. Many "this can happen" or "that can happen" situations happen more often than they don't.
For example, when Toxitron and Electron are out at the same time, you'll often be dealing with either the Lightning Conductor being pulled in and hurting the raid, or the Shadow Infusion will be going off while Toxitron is spawning adds.
There's less RNG to the fight than it seems, but it's still a whole lot to keep an eye on.