I take it you’ve read Dulfy’s guide for a basic overview.
We’re going to be talking team roles here for smoother, less agonizing runs.
Just to clarify here, this is not the ultimate strategy guide, follow or else kind of thing. I believe in multiple strategies working well and GW2 supports that. If you play with various guilds and preset dungeon groups, one will tend to find that these closed groups evolve their own set of strategies that work perfectly well. This is just to help those who are close to beating their head in after failing multiple PUGs and wondering if there is -any- rhyme or reason to this dungeon.
There is.
I mean, you could just run in all willy nilly and hope that everyone magically synergizes and all will be well. But judging by the amount of failure cases and party members bailing mid fight and GW2LFG posts that read “at such-and-such boss, need 1 or 2 or 3 more,” here’s what I’ve observed so far:
There’s basically “It” and “Not-It.”
That is, the person whom the mobs are focusing on is “it.” This person usually has the highest toughness of the group. You are the de facto tank. No matter what your class is. Stop screaming and learn how to play it well.
The other people who are “not-it,” that does not mean you can relax and leave “it” to scream and die. If “it” dies, another one will become “it.” And so on until all of you are dead. Your role is a damage-support hybrid.
I speak of support in a very broad sense. Broader than even the typical GW2 use. I don’t care if your version of support is killing the mobs very very fast in all berserker gear, but if you choose to do that, you better do it very well. Better yet is if you can slot some group condition removal or blinds/dazes/interrupts/controls or reflects at certain points in the dungeon, and/or ways to buff up the party and debuff the mobs with conditions, along with doing damage.
All of you will need to move well. Or at least, competently enough.
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Aetherblade Trash Mobs
Generally not too big an issue. Taskmasters confuse, so if your group loves to put stuff on auto-attack, it’s a good mob to prioritize killing first, if you’re not just going to AoE ’em all down in tons of cleaves and blasts. Projectile reflection and absorption appear to help mitigate some of the damage from the ranged Aetherblade mobs too.
The pain happens in the spawns with Aetherblade Strikers in them. Their lightning channel is not a projectile. It WILL kill your tank unaided. Especially if two are on him/her, with everything else. Support support support. Offtank it or get a pet to, daze/stun them, blind the eff out of them, pull them, interrupt them, focus fire, whatever. It’s especially fun with a taskmaster in the mix as well, call targets if possible. Prioritize both of these, one after the other.
The Practice Room With Thumpers and Cannon Fire
If your team is awesome, you could really just charge into it all and sidestep the cannon aoe. It may be good practice for some people.
My random team here kindly demonstrates two possible ways to chokepoint the mobs and avoid the majority of cannon fire. I’m sure there’s more.
Just hanging in the corner and/or running under the bridge/staircase also works to LOS stuff, but cannon fire may hit.
Please learn the art of the corner pull if you do not know how. This means everyone gets out of sight, preferably in the same spot behind a corner, so that ranged mobs will walk towards you.
The tank, or just a ranged guy, range attacks the mobs and then trots back around the corner with everyone. The mobs will cheerfully follow and you can then pile on with melee and AoE. Just keep an eye open for cannon fire in case some person gets out of position accidentally. Corners and GW2 camera angles can lead to blind spots.
Mid Boss – Champion Frizz and Golems and Lasers, Oh My
Some groups may prefer to clean up all the adds before working on Frizz. Others may simply start off the lasers by lowering Frizz’s health to the requisite amount. Apparently the adds die from the lasers after a while. I’m not 100% sure on that last, but certainly after a while, they seem to die in all my groups – whether it’s from teammates killing them or not, dunno. Doesn’t really matter, imo.
Phase 1 – Low Lasers
Yes, you can jump on the crates and stay there and range.
All except IT, that is.
If the aggro-holding person remains rooted on a crate, what will happen is every time the laser spins around, the golem will get a shield buff and block attacks.
Yes, you can just autoattack your way through it and wait for the buff to fall and damage it intermittently between laser spins. It’ll work, but it’ll be annoying.
Ideally, de facto tank should be running in an anti-clockwise fashion, following the laser spin and kiting the golems away from the laser. Your role is not so much as to do damage, but to a) not die, b) try and dodge or stability, or just stay far away enough through potential pulls which may screw up your nice pattern.
This leaves the golems free of the shield buff, leading to faster dead golem. All the rest should be a) not dying, b) attacking unshielded golem.

Phase 2 – Laser Wall
Same idea here, except all the not-its cannot just camp out on a crate.
Run around the room. Don’t die to the laser wall. Shoot or melee golems. Don’t get in the way of their spin attack or their pull. Help “it” stay alive. Watch confusion and dat autoattacking.

Also note how the laser extends across the whole room in a straight line and rotates as one line, not clock hands.
Phase 3 – ALL OF TEH LAZ0RS
I want to point out something rather obvious that I personally never saw while I was running/screaming/dying as the tank. The lasers go in a straight line across the room.
That means you only have to keep an eye out for essentially two lasers and that sneaky low beam laser, well, if you see one side, you can roughly extrapolate where the other side is and how soon it is creeping up behind you. It is not two evil low laser beams acting like clock hands that sweep at random speeds out to get you and have to be madly jump-crated (which was my first impression of it.)
That also means that you can then evaluate whether you want to stay on the crate and let the low laser sweep by you, or hop off immediately on the safer side (the side where the low laser will move past), or if you have to jump to the risky side (the side a low laser will be approaching) and make a mad dash to a further away crate – the latter option in cases where say, the laser wall is about to squeeze you in if you jump to the safe side.
Ok? Same deal. Tank guy should be kiting the golems away from the lasers as best as possible. Should, anyhow. Focusing on not-dying is, frankly, I think the best thing to do in this phase. Try and get the laser pattern down, jump on crates and off them appropriately, keep as near the front as the laser beams will allow.
Everybody else. Also focus on not fucking dying (easier said than done, I know) and watching out for the shield buff to drop to unleash your attacks on the golem. When you are confused, do not attack yourself to death. Just look away from the damn golems and look at the lasers and stay alive.
The pull is a nuisance that gets in the way and will screw things up here and there. Stability helps, but you know, it will never be 100% uptime. Bad luck happens.
If “it” dies, role swap time! New “it” gets to be the tank and kiter! On and on until there were none. (Either way, no golems or no more players.)
Of course, if you are full of awesome, you might even be able to solo the golems. But then, you wouldn’t be needing to read guides like this.
Final Boss – Horrik and Mai Trin
This is really a fight about aggro control and positioning.
Mai Trin bleeds if you stay in her melee range. That means, if your teammates plan on getting close, and even in the case where you don’t but want to prevent accidents, bring lots of group condition removal. My suggested help out time is when bleed stacks hit 10-12.
Tank person who is it. Your job is to be kiting Mai Trin. Possibly at range. At preferably just a little further away than her melee range. You want to be kiting her over the electrical blue AoEs that will pop up when Horrik shoots his stuff.
Not-its. You generally want to get as close to Mai Trin as possible as well, be it range or melee, so that if and when Horrik shoots his AoE and it happens to be a blue one, it’s easier for tank person to kite it over. As her shield stacks fall off to 6 or lower, she starts taking damage and it is possible if very very slow to lower her hp down, regardless of whether more shields pop off or no. If you want it faster, then you have to take more risks to getting the blue aoe to overlap on her.
Once conditions start landing on her, one can cripple or chill to slow down her movement over the blue aoe as well, or if you’re really sophisticated, you can play with taking off her 5 stacks of defiant and then dazing her over the aoe and so on.
One interesting spin-off role that a good “not-it” can play, that I’ve been evolving, is a way to control the damage done by Mai Trin’s shadowstepping. You are THE FURTHEST PERSON. Please make sure you can dodge and observe her animations. If you can block consistently (or leave mesmer clones to absorb the attack or whatever), even better.
See, what usually happens is that the “worst” or most nervous and/or squishiest or lowbie character in the group gets all twitchy and starts edging further and further away from the mess. Before you know it, BOOM, she shadowsteps into that person and eats him or her for lunch. Then now everyone has to drop everything and waste time rezzing, and when you rez, you risk becoming the furthest person and ZAP, another teleport happens and… well, it gets MESSY.
My theory is, what if we prearrange a good or at least, sturdy player to be that furthest person? Note, this cannot be it, or the tank. A not-it gets to step up.
Your job is to arrange yourself so that you are the furthest person at all times. You primarily watch out for her animations (which can be hard with all the particle effects flying) and do your best to dodge (forwards, seems best) when you see her do the characteristic finger point which means she’s going to come to you. If you manage to time it right, and the projectile hits during your dodge invincibility frame, you seem to actually block it and she doesn’t teleport at all. If it’s not timed right, well, at least you’re out of the way and won’t get too bled up when she comes over. Have condition removals for her bleed and cripple in event of accidents. She will then promptly go right back to IT. (Secondarily, you can do damage as well, of course.) If you have blocks on demand, this makes your life even easier.

Also, the GWAMM tanking this was an engineer. There was another warrior and a guardian in the party. Players, not classes.
As for the Cannon AoE phase, there’s two methods. If you are really sure that your entire group has nearly equal ping to yours and will be applying group swiftness and group healing, and can stay all nicely neatly balled up together, you can run around the perimeter together staying ahead of the AoE. It looks really really awesome if done correctly. What usually ends up happening, just as in WvW zergs, is that you don’t get a nice neat little ball, you get a train or a snake. Someone falls behind. This someone is promptly PWNED by all the aoes that have carpetbombed the place. Depending on your group, this may end up as multiple someones.
I have actually found it much safer in PUGs, where people could be from all over the world using computers of differing quality and framerates and certainly not on voicechat and used to stacking and moving as a ball together, to do the spread out and move as little as possible method.
What usually happens is a person in each corner and one in the center, more or less. Just move the distance necessary to a clear spot away from the aoes, and stay still until the next aoe is about to hit your position. Save your dodges for when there is no way out that you can just move to. Survival rate is usually 3 or higher, which is sufficient to rez safely during the next Mai Trin and Horrik phase.
It goes without saying that one should NOT BE REZZING while the place is being napalmed. Survive first, only save people if you think you see an opportunity and are awesome. If you die doing it, then well, leave them for later next time.
Rezzing strategy: Tank/It, you do your kiting thang. Other people rez. Other people must also be KEENLY aware of Mai Trin’s finger-pointing so that one can dodge or block if you become the furthest person while rezzing.
Really, all this does is waste shitloads of time. Don’t fucking die. And if you are not awesome, don’t fucking bring your squishy lowbie into this dungeon.
Please note that in all of this, I have not expressed ANY CLASS-ISM whatsoever. Stop fucking begging for guardians and warriors or heavies. Some of them may not be IT-specced. I have seen some awesome necromancers and engineers also kite and control Mai Trin perfectly well. I’m sure other professions can do it too, I bet a mesmer could as well, just haven’t seen it in play yet – except you know all the rest tend to love sitting in berserker gear.
All it requires are players to recognize the de facto role that their party needs and be flexible.