The Ankh
The basic mechanics of the Elite 5+ version of The Ankh. If you’re familiar with Nightmare Ankh from TSW, much of this will be familiar, but it’s not the same!
Squalid Hekaturgist: He is standing in the middle of a circular area, and four Motes of Aten float around the circle. The motes themselves are very dangerous and will eventually kill a player that they stick too, so take care not to get too close to one. Three of them will periodically cross in the center and across; not all of them will, so they’re not always easy to predict. They silence the player they are attached to and do a lot of damage, so if you get moted, someone needs to free you. The Hekaturgist himself moves away from the tank, so circling around him will generally keep him in the center. He casts Heka Blast, a targeted AoE on random players, which can’t be stopped. It won’t kill the person it targets, but it will kill anyone else inside it, so the person with Heka Blast should stay still as much as possible and let everyone else move.
Doctor Klein: He stands at the head of the bridge, accompanied by a Dimensional Reaper, which protects Klein from damage. It’s best to pull the Reaper down onto the bridge with Evulsion or a pulling gadget, as standing on that side of Klein opens players up to being moted when Klein casts Open the Void (which opens a portal to his left or to his right that lets out three Motes of Aten). When the Reaper dies it drops a knock down AoE on the player it had aggro on.
Klein also casts Profane in the Membrane (which can be interrupted), his normal attack, one Swell of Mutation (a small wave to the left or right) or three Swells of Mutation (left right left or right left right). He always signals the side he will cast on by turning that way and lifting his staff. Strafing left or right will avoid the attacks on the other side.
Every so often, he will raise his staff, a purple beam shines from Klein an the tank, and he casts Dreaming Shroud on the tank, which is ten seconds of up to 4,000 Filth damage a second. This, as one can imagine, hurts. One way to survive this is for the tank to use Twist Fate + passive as soon as they glow purple, and then have the healer use everything they have to heal the tank through the last five seconds. Pain Suppression with the passive is another way to really help out the healer. After Dreaming Shroud, Klein will cast Wave of Mutation. This wave takes up the entire bridge, so you’ll need to run back and stand on the fallen pillar, which will have Filth on it. The wave can be jumped (if you know how to do that from TSW); Superliminal Bridging Device used at the right time will jump it, Flicker works, or the tank can use Immutable to survive the wave and then heal up right after. Anyway, Klein start casting again, but he’ll stop for a short time the first time someone hits him after the wave, which is why jumping the wave is so important. Dodging and weaving back is really hard.
When Klein is finished casting Open the Void after a wave, yank down the new Reaper and kill it.
If he casts Open the Void any time other than right at the start or right after a big wave, stun him as soon as its done to hopefully prevent him from spamming Swell of Mutation at the same time.
This is accurate for the last fight as well.
Orochi Dead Ops: They drop Frag, a large explosive AoE under someone’s feet, and Closedown (which can be interrupted), a hinder on the tank. With one left, he or she casts Full Clip, a column attack with no chalk, plus the other two attacks. Pick an order and kill them in that order. While tanking this, I find having a taunt on hand is useful just in case someone drops a High Explosive Grenade on all the Dead Ops at once.
Dimensional Arachnid: The spider randomly spews unstoppable Black Bile under a random person’s feet. At the start of the fight and periodically during, research scientists show up and buff the spider. The five scientists should be killed at the start, then picked off as they revive. The scientists attack with Heka Strike when aggroed, and also have an annoying habit of resetting if moved. Sometimes the Filth puddles may become invisible, not sure what may cause this, but be aware of where the puddles are.
The Colossus, Melothat: First off, the two mummies and the first gate needs to be knocked down, then the mummies behind the gate (or you can just break the gate and let the tank be swarmed by mummies 
A chaos tank will eventually kill them with Singularities). After this, the DPS should stay on Melothat while the tank runs up to the next gate. This giant juggernaut of a skeletal mummy does not like his toes stubbed. In order to not stub his toes and trigger a massive, damaging, Exposing Overkill when in melee with Melothat, stand at the farthest extent of your range. It helps to defensive target yourself and angle the camera low enough that Melothat’s red circle always shows–don’t let your green circle and his red circle touch, and he won’t punt you.
After doing enough damage to him that he roars and starts glowing red, retreat past the gate, open the second one, kill some mummies, while everyone but the tank ignores the Orochi Dead Ops there, then start attacking Melothat again. The Orochi uses Closedown and Frag, so the tank needs to keep the Orochi well away from the DPS. Melothat will start bringing Wretched Receptacles from behind him, which cast Hekaruption, a quite damaging cast, so kill them fast; the tank will be too busy entertaining Orochi to help. Melothat will charge a second time; get behind the gate, and kill him there. When Melothat starts moving forward at the second gate, two more Orochi will show up, so the tank should have the first Orochi way in the back and keep all three busy there. If you hear Klein tell you to hurry up and die, Melothat is coming close to Overkilling you over and over into the Filth wall at the end of the bridge, and room gets tight there with three Orochi and their Frags.
Melothat and Klein: Melothat casts uninterruptible Sinkhole, an AoE on the tank that leaves very dangerous Filth behind. Melothat has a pretty substantial cleave too. After 75% of his HP is taken down, he’ll fall over and Klein will start buffing him. While Melothat is kneeling, he will have a buff that protects him from all damage; I think it falls off when Klien stops buffing him. The tank needs to run upstairs, punch Klein, then use the scaffolding just below Klein to get back down into heal range. When Melothat stands, he seems to reset aggro, so a taunt is needed. After he kneels down a second time at 50%, Klein will have moved farther up the scaffolding, but he’ll still need to be punched. A Wretched Receptacle will spawn out of the Filth puddle left by Sinkhole aster Melothat stands up a second time, which is nice to kill. After the third time, at 25%, Klein will teleport down and cast his Wave of Mutation.
Klein’s wave needs to be jumped at this point to make him stop spamming skills; after a while he’ll port over to the other side of the room and spam motes and waves. Sometimes, if Klein is damaged too fast at this point, he’ll retreat upstairs but leave a second Wave of Mutation as a parting gift; I assume this is a bug, but regardless, be aware of it. It’s much easier to deal with this second wave if you don’t also have Melothat to drag around and cleave everyone.
Once Melothat is dead and Klein is damaged enough to retreat, Klein summon two Dimensional Reapers and will begin casting an apocalyptic skill that, if no one gets upstairs in time to get his attention, will wipe the party. It’s pretty long, so it’s not a threat. Drag down a Reaper, kill it, kill the second one, then kill Klein; Klein casts interruptible Profane in the Membrane until the end.