|Omnotron Defense System during the chaos|
First up is the Omnotron Defense System in Blackwing Descent. This fight is actually the joint-first fight in BWD, but because I have a DPS offspec I have not yet tanked Magmaw, so it's the first one I'll write about! For a post about Magmaw, see the Primal Precision blog. It is hereafter referred to as ODS, although it is not odious but actually a lot of fun.
Continuing your mission to clear out Nefarian's rubbish, ODS consists of 4 robot constructs who activate in turn, but yet have a shared health pool. Each construct has an energy bar and when activated, it is at full (100). By using abilities, the constructs energy bar depletes - at half (50), a shield is popped and a new construct is activated, and at empty the construct deactivates. The next construct to be activated is not random, but fixed, but the order is random when you first engage, so you really don't know who is going to be next, unless you've already wiped and seen the order once through. You have 2 constructs active at a time, apart from at the beginning where you have only one.
Pro tip: If you are on the second construct, DPS in Cat form at the beginning before it activates.
Each construct does various abilities which the DPS and healers need to worry about, and each one's abilities are unique. This means when you get construct X and Y up, the raid needs to worry about the abilities of construct X and Y and deal with them.
We run with two tanks, one per construct. Generally you position the two active constructs apart, but be careful not to back up too far into a corner so that the healers cannot reach you. I tend to keep them on the outside edge of the room, with me stood closer to the middle.
Regarding the construct switch, you will be tanking one bot and DBM will show a shield warning as its energy gets to 50 and it pops a shield. At this point you never want to attack the shield, because they all do nasty things. Just press esc or de-target the construct. Now it will continue to attack, and after 10 seconds its shield will go and you can continue building threat. I tend to pop a cooldown like barkskin and just stand there dodging until the shield goes. Now you can see a purple beam going to the next construct which will be activated, so make sure you can see it to target it. When your construct gets to 0 energy, it will cast a shutdown spell, the next one will activate at the same time and if it is the first time the new construct is up, it will run off after a healer. As soon as the new construct activates you need to FFF and taunt it, then get some threat on it, especially because the DPS will switch to a construct when it activates, so they will be damaging your construct. If it is the second or subsequent time activating, the construct will come for you because aggro is not wiped, so it's easy, you should have a big threat lead because you spent the time from energy 50 to 0 just tanking it on your own. I tend to get both constructs in the same place and stay there (unless I get a green cloud under me).
Basically you just end up getting one bot after the other, with two of them alternating, and you can usually stand in the same place. The other tank will be always tanking the other two bots.
When you get a specific construct to tank, what you need to do depends on which one it is:
The nature damage construct. He puts Chemical Bomb on the floor which increases damage done to anything in it by 100%, so if it gets put under you, get out of it ASAP. It looks like a green cloud of smoke.
Pro tip: Pulling your tanked construct into Chemical Bomb will increase damage done on it by 100%, so if possible, get those bots in the green cloud.
He summons bomb adds with the Poison Protocol spell. These adds fixate on a raid member and travel slowly toward them, and need to be killed before they reach their target, otherwise they will explode. We get 3 on 10 man. This is why you need to keep him away from the other construct (and the rest of the raid), because when he summons adds you need the adds to travel the maximum distance to their target. The raid will be around the other construct if Toxitron is below 50 energy, and won't be paying attention to adds, so sometimes you need to shout out when he is summoning them.
Furthermore, if you are tanking another construct and Toxitron is up, you might get fixated on and an add will come for you, so you need to pay attention to DBM warnings when Toxitron is active. Luckily the bomb targets are not stunned, so you can kite the construct away from the bomb until the DPS kill it.
The arcane construct. He puts a puddle of Power Generator under himself, this increases damage done by anything standing in it by 100%. You need to move him out of this puddle, and make the DPS and healers aware it is there, so they can stand in it.
Pro tip: Move him just out of the puddle, so the melee can stand in it and enjoy the damage increase.
Interrupt duty is required on Arcanotron, he casts Arcane Annihilator on random raid members, which really hurts. There needs to be an interrupter on him all the time he is active, even below 50 energy when the rest of the raid have gone off to damage the newly-activated construct. When his shield goes up, stray attacks like dots will increase his casting frequency of Arcane Annihilator, so one interrupter will not be enough. So you may be needed to help interrupt here, coordinate with your interrupter, although now skull bash can miss it's not guaranteed. Last time I alternated interrupts with a rogue, calling out on vent who's turn it was to interrupt.
The fire construct, his abilities are not that interesting if you are his tank. However, he does do Acquiring Target which sends red beam to the target and then fires a conal AOE to it. If you get targetted while tanking a different construct, the usual strategy is not to move and the rest of the raid get out of the way of the conal AOE, so erm stand still.
He also does Incineration Security Measures which damages the raid, so you can pop a cooldown at this point if you want, although it only does 60k damage which on a health pool of 150k, is not that much to worry about. Your friendly tank healer should be able to cope, still such magic damage is what the Mirror of Broken Images is all about.
The electrical construct, he is very straightforward to tank. He will cast Lightning Conductor on a raid member, who must move away from people. If it is cast on you while tanking him or another construct, you have to stay put and get the melee to run away, or if you're on your own, it's all good.
Once you figure out what to do when tanking each construct, and what to watch out for when another construct is active, the fight settles into a rhythm and will soon be over. Nice loot is Poison Protocol Pauldrons and Lightning Conductor Band.