First off, the trash before this boss is complete ass. Expect to wipe on it as much as you wipe on the god damned boss.
Secondly, there’s a lot of shit going down in this fight (o hai, WELCOME TO CATA) so I’ll break it down as best I can without confusing myself. I’ve also only had a few attempts on this fight so feel free to correct anything you see wrong in the comments!
Important note: the elemental monstrosity of the final phase appears with the combined health of all 4 bosses, which is why it’s important that each pair of bosses be DPS’d as close to equally as you can manage. The phase changes at 25%.
The bosses in this phase are Feludious and Ignacious. From here on out they shall be called Water Boss and Fire Boss.
If you’re the water boss tank, interrupting hydrolance is key. You will also wish to tank him away from everyone else because Glaciate damages everyone around him and sucks balls.
If you’re the fire boss tank, be prepared to help the DPS interrupt rising flames after his fiery shield is down. Don’t position him too far away from the fire he’ll periodically leave on the ground because the melee will need quick access to it. Speaking of said fire, every so often the boss will charge off, but he’ll charge right back, trailing the fire behind him.
Heart of Ice and Burning Blood will be two debuffs put on the raid. While you do want to cleanse these you don’t want to do it immediately, as a few ticks can provide a DPS buff.
Hydrolance should be renamed Hydropunchtotheface.
You will be on the fire boss. This phase is cake for you compared to the next one. If you get Waterlogged, briefly step into the fire. Try to not cross in front of the boss while getting to said fire because he also does a frontal cone of fire and, well, your healers like their mana.
After the fire shield (which needs to be DPS’d down ASAP) you need to interrupt the hurty flamey thing he’s channeling, Rising Flames.
If you get the Burning Blood debuff and a ranged you like is near enough for a hug, go ahead and g ive them one because it will increase their DPS on the water boss. I wouldn’t run halfway across the room for it, though.
You will mostly be on the water boss, though the two bosses should be kept as near in health as possible.* One of you should probably be designated to switch if necessary.
If you get the Heart of Ice debuff, run and give the melee a hug. Yes, that’s right–if you get that DEBUFF, run and give your guildies a hug. It’ll increase their DPS on the fire boss.
If you get waterlogged, dart through the fire that the other boss is leaving on the ground. If you don’t the water boss will freeze the blood in your veins and well, that just doesn’t sound very pleasant. Your healers will probably let you die for your fail.
A few words about gravity wells and cyclones, as these apply to everyone:
The air boss summons a cyclone you’re going to want to find it. Yes, run TO the cyclone, those things you avoided on every other boss encounter ever. Yeah. It’ll give you a levitate buff that you need to not get gibbed by earthquake.
After earthquake, you need to run to a gravity well so that you get lose the levitatey thing so that you don’t get thundershocked to death.
Each of these much-needed buffs will probably be all the way across the room from where you are. Or on top of each other.
Also: if you get lightning rod, get away from everyone else.
The earth boss tank should try to keep an eye out for Harden Skin to interrupt it. Your melee will be doing this as well, but with everyone running around willy-nilly, it’s best to keep all eyes on it.
The air boss tank should…tank the air boss. He teleports around the room just to piss you off.
There’s a lot of damage being tossed around. You should heal that.
(Do you have people in your guild who state the obvious like that? We do. Do you want to slap them? I do.)
The only thing of note that I recall for this phase is the Lightning Blast that is thrown at the air tank after the boss teleports.
Find your way to the earth boss. Don’t forget to pull out your razors as you go, because this phase blows (see here).
Try to interrupt Hardened Skin. You know, during all that time you’re not running around looking for a cyclone or gravity well.
Every so often the boss will cast Eruption, shoving spikes through the floor around him. Try to not be standing there.
You will mostly be on the air boss. He teleports around like a dick. If the earth boss tank/melee miss a Hardened Skin interrupt, you should help those scrubs DPS through it.
The one of you that can do the best gimped DPS while in tank gear should try to do that, because this is a 1 tank, DPS race phase. The tank-tank should drag the boss out of puddles (think blue defile).
Quote from Kotakh, SiB Resto Druid: “omfg all that damage incoming wtf heal heal heal heal oom /dies fuck that noise”
So, in essence: don’t stand in puddles, heal the fuck out of people lifted off the ground in Gravity Crush, and flail madly at your healing buttons. Remember, let your least favorite people die first!
Don’t stand in puddles. Don’t stand on things that look like flares. Blow any self-heal or damage reduction abilities that you have. DPS the fuck out of shit. Use any major DPS abilities (heroism, army, etc) in this phase as well. DPS the fuck out of shit HARDER. BEFORE YOU ALL DIE. If you get lifted up in gravity crush, I hope you bribed your healers well.
Spread out to minimize damage from lightning. For the rest, you can actually see the melee section above.