Maloriak is one of three "second-tier" bosses in Blackwing Descent. It's a unique fight due to an interesting mechanic about adds. There are a total of 18 adds that Maloriak will attempt to release, 3 at a time. These casts can be interrupted, but there's a catch - once he reaches 25% health, he will immediately summon all the remaining adds, in addition to some larger, meaner ones. Therefore, it's crucial to have as few adds as possible remaining when you push him into phase 2 (ideally zero), but it's also important not to have too many loose at once earlier in the fight, or else their damage will overwhelm and kill your off-tank.
Maloriak also uses a very lethal pulsing ability called Arcane Storm that must be interrupted immediately. Finally, there's also some basic positioning mechanics (stack up, or spread out, depending on what Maloriak is doing).
For a Frost DK, we will likely be in charge of interrupting either Release Aberrations or Arcane Storm, since we will always be in position to interrupt and because our interrupts are free (assuming you're specced into Endless Winter, which you honestly should be). This is actually a lot trickier than it sounds.
Your special class/spec responsibilities:
• Interrupt Release Aberrations OR Arcane Storm (not both!)
• DON'T interrupt the other spell
• Seriously, don't even think about it
At first glance, our job sounds easy - just interrupt X spell! However, it can be extremely frustrating depending on your personal reflexes, your raid makeup, and how well your other interrupter(s) do their jobs. Additionally, the real challenge in this fight isn't interrupting, but NOT interrupting. All those lighting-fast reflexes you've trained and practiced that let you interrupt anything at a moment's notice? Throw them out the window. If you interrupt wildly and without thought, you will wipe your raid on this fight.
The main reason you need to be careful about your interrupts is to not waste your Mind Freeze. For example, if you're supposed to interrupt Arcane Storm, but you accidentally interrupt Release Aberrations, your Mind Freeze will still be on cooldown when Maloriak casts Arcane Storm. Better hope your Strangulate is available, or that someone else can cover your mistake! If you're a Blood Elf or Tauren, at least you have a backup emergency interrupt. But otherwise? You're screwed.
Why doesn't the person who was supposed to interrupt Release Aberrations just swap with you and get the Arcane Storm? Well, it'd be nice if they could, but they were probably doing their job properly and ALSO interrupted Release Aberrations, meaning their interrupt is ALSO on cooldown. This is why it's important to stick with your designated spell to interrupt and NOT touch the other one.
As if that wasn't bad enough, interrupting a Release Aberrations cast that was supposed to go through can be devastating. Whoever is in charge of handling the adds has the tricky task of interrupting some, but not all, of the Release Aberration casts. For example, if I'm in charge of adds and I plan to interrupt the first cast, and then let the next three through, everything gets thrown into disarray and chaos if someone else interrupts one of those "let through" spellcasts. Suddenly, we don't have as many adds as we wanted, and have to deal with more adds (and therefore, more offtank damage) later on, or during the last phase, either of which is usually a fatal burden.
I actually highly recommend turning off the spell you won't be interrupting in Deadly Boss Mods, so you won't be distracted by timers or warnings for something you should be ignoring. I'd also suggest the other interrupter do the same, for your spell.
Here is a breakdown of your individual duties, depending on what you'll be interrupting. Note that in both cases, you will stack in front for the red vial phase and spread apart in the blue vial phase. Also, if you get a fire or frost debuff you have to move away from anyone else. In all cases, however, STAY CLOSE ENOUGH TO INTERRUPT. Finally, you Howling Blast the hell out of the adds in the green vial phase.
At all times, if you interrupt the wrong spell and cannot get the proper one coming up in a few seconds, call it out IMMEDIATELY so hopefully someone will be able to get it and save you. Do not hesitate! You can feel bad about messing up later, but right now it's CRUCIAL someone gets the interrupt, since you cannot.
You're interrupting Arcane Storm! :D
Congratulations, you got the easy job! Interrupt Arcane Storm with Mind Freeze whenever you see it, don't use it on Release Aberrations, EVER. Not even if the person who's supposed to be looking after it says that can't get it. If that's the case, someone else has to get it, because your job is to STOP ARCANE STORM. Now if your Strangulate is up, or if you have a racial interrupt, then feel free to help out. But you HAVE to make sure your Mind Freeze is reserved for Arcane Storm.
During the green vial phase, the adds and Maloriak should be stacked up together. He will still cast Arcane Storm during this phase, so you can't afford to switch targets - focus on him and Howling Blast the adds around him, and keep interrupting Arcane Storm. There are ways to still watch him while targeting something else, but I prefer to play it safe and just stay on him. It's not like it will be hurting your AoE add DPS anyway, since Howling Blast will hit everything around Maloriak.
You're interrupting Release Aberrations! D:
You have the hard job! First things first - Release Aberrations casts pretty fast. Keybind your Mind Freeze to a readily-mashable key, and be ready at every moment to hammer it. This is the only fight where I actually change my Mind Freeze to an easy key (middle mouse button) so I can hit it instantly.
If you have a warlock, it's your lucky day! Ask them to put up Curse of Tongues, as it will slow the cast time down and give you a bit of breather time. An Arcane Mage's Slow works too.
If you have neither, don't panic. Time to break out a rarely-used ability: Necrotic Strike. Try to have it up at all times so you don't miss any Release Aberrations interrupts. Unfortunately for us, Necrotic Strike's debuff is dispelled if the target heals a certain amount, and Maloriak DOES heal himself with Remedy. Watch to see if the debuff falls off, and harass your teammates to spellsteal/dispel Remedy ASAP. (They should be doing this anyway.)
As for the adds, there's a variety of ways to do this fight, so I'm not going to offer specific advice. What I will say is be sure to call out how you'll be interrupting, so your raid is aware and most importantly, so your off-tank knows. Your OT should also be communicating with you to keep track of how many adds are currently out, and how many more you want. For instance, after the first green vial phase, when Maloriak is dragged back to his cauldron, I announce how I will be interrupting the next few casts, so everyone is on the same page.
During the green vial phase, the adds and Maloriak should be stacked up together. He will still cast Release Aberrations during this phase, so you can't afford to switch targets - focus on him and Howling Blast the adds around him, and keep interrupting Release Aberrations. There are ways to still watch him while targeting something else, but I prefer to play it safe and just stay on him. It's not like it will be hurting your AoE add DPS anyway, since Howling Blast will hit everything around Maloriak.
There are many nice opportunities for Anti-Magic Shell, including two "run out of the group" debuffs (Biting Chill and Consuming Flames), and the "stack on the tank" attack, Scorching Blast. The entire second phase is also full of crazy magic damage, so if it's available, use it!
If you get him to 25%, and all of the 18 adds are dead, rejoice! The hard part is done. There won't be anything else to interrupt, just burn him down and stay out of fire on the floor and away from exploding ice orbs.
Maloriak drops Belt of Absolute Zero. He also drops Dragon Bone Warhelm, which is actually a tank helm (look at the socket bonus) but is still pretty good for us. Don't take it from your tank, but if they don't need it you could certainly do worse. I don't view the +Stam socket bonus as wasted - after all, if it were a yellow or blue socket we'd likely just be ignoring it and gemming pure +Strength anyways.