The problem is that while she has a number of mechanics to watch out for during the course of the fight, they’re largely simple ones so if you’re one of those that can pretty quickly grasp the various mechanics of a fight within a few tries, oh boy, be prepared to tear out what’s left of your hair if the rest of your group isn’t quite there with you.
As the fight starts, Hagara starts in a neutral phase that she slips into in between her other phases.
As a tank, the only real thing that you need to keep an eye out for is her Focused Assault. While she channels, she’ll attack much more quickly but will also be rooted in place so all that you really need to do is take a few steps away from her while this happens and keep an eye on the threat levels of your raid when it ends to make sure that she doesn’t end up rampaging after someone else in the raid.
She has a couple other abilities but they’re nothing that should effect you or your job directly.
After a relatively short period, Hagara will transition into the next phase of the fight, either the Lightning Phase or the Ice phase. Which one she initially selects is random but after that first choice, she’ll simply alternate back and forth between the two of them so you’ll always know what’s coming.
For the lightning phase, four crystals will spawn at the edges of the platform along with a lightning elemental will spawn that needs to be picked up by the tank. The elemental doesn’t really do anything scary on it’s own but once it dies, it will overcharge the nearest crystal and destroy it so you might need to coordinate with your raid so that everyone’s on the same page about which crystal will be blowing up.
Once a crystal is destroyed, it’ll send out bolts of chain lightning to anyone nearby which will then jump to other players until your raid chains it to the remaining crystals, destroying those as well. Hagara also channels a lightning spell that will hit a bunch of random targest in the raid, leaving them with a stacking damage debuff so if you notice your stacks growing higher than comfortable, don’t be afraid to hit a cooldown to endure the remainder of the phase.
The ice phase similarly has four crystals to destroy. The catch in this phase is that the center of the platform becomes very damaging and four waves of ice rotate around the platform in a clockwise manner. What this means is that your raid will have to be running laps around the outer edge of the platform while knocking those crystals down. There are also icicles that will be landing periodically from the ceiling to make the marathon a little more dangerous but nothing relaly to write home about.
Hagara will alternate between one of these phases and her neutral phase so once you’ve seen them all, it’s really just a matter of getting everyone on board with the simple strategies for each phase and you’ll pull through.