All: Use the four levers to match the central totem's four blocks, numbered 1 to 4 from bottom to top, to the three smaller totems around the room: blocks 1 and 2 on the left totem, blocks 2 and 3 in the centre, blocks 3 and 4 on the right. The solution is randomised per instance.
Hard Mode: Activate the Challenge Banner located outside the entrance gate to the arena, just to the left before entering the room (Veteran only).
All: When he teleports to the edge of the room, move clear of the room-wide rectangular beam he fires. He does this twice in succession before resuming the fight normally.
All: Move out of his periodic poison explosion, centred on the boss. There are a couple of seconds of warning.
Tank: At 65%, 45% and 20% health he retreats to the centre and becomes untargetable, spawning adds each time: a Nix-Ox and Nix-Hounds, then an Iron Atronach and Flame Salamanders, then smaller enemies. Taunt them and hold them stacked.
Dps: Destroy each Shadow Phase's adds quickly: the Nix-Ox at 65%, the Iron Atronach at 45%, the smaller adds at 20%. He remains untargetable and the fight does not resume until they are dead.
All: Hard Mode only. An uncleansable poison effect follows each player and deals heavy damage. Stay loosely grouped: close enough to be healed together, but far enough apart that the poison effects do not overlap and double someone's damage.
All: Hard Mode only. During the Shadow Phases, shadow copies of Kovan appear around the edge of the room casting the same rectangular beams as his teleport. Track all of them, not only the one seen most recently.
Healer: Heal the captive Argonian Behemoth Beexilko, chained nearby. He starts weak and regenerates slowly; once strong enough he breaks free and stuns Urvel Drath for a few seconds, after which Urvel re-stuns him with a lightning spell.
All: Move away from the lava pillars he spawns periodically. They spread outward and linger for a few seconds before fading.
All: A red rune above your head means you are the target of Seeking Flame, a slow-moving fire effect that follows you and deals heavy damage on contact. Lead it away from the other players; it is slow enough that you can keep attacking the boss while you do. It can instead be led onto a blocking tank, who takes very little damage from it, if the group agrees in advance.
Hard Mode: Activate the Challenge Banner located just outside the arena room, right next to the entrance doorway before crossing the threshold (Veteran only).
Tank: Block her Charged Heavy Attack.
Dps: Dodge roll the Charged Heavy Attack if it is not aimed at the tank.
Dps: Destroy the Darklight Orbs she spawns at the edge of the room before their tether kills the tethered player. Interrupting an orb destroys it instantly, which is faster than reducing its health.
All: At 70% and 40% health she plunges the room into darkness. Stand in one of the two lit safe zones, or the darkness kills you. One zone starts centred on her, the other on a friendly NPC. Stand in her zone first, wait for her to throw ground effects near it, then move to the other zone as she relocates and takes her light with her.
Dps: Kill the adds that spawn during each Darkness Phase.
Tank: After each Darkness Phase ends she beams you for about 10 seconds. It cannot be interrupted; mitigate it and hold.
Healer: Focus heals on the tank through the roughly 10-second beam after each Darkness Phase. It cannot be interrupted.
Tank: Hard Mode only. The beam after each Darkness Phase strikes three times at once rather than once. Mitigate heavily and use defensive abilities.
Healer: Hard Mode only. The tank takes three simultaneous beams after each Darkness Phase rather than one. Have burst heals ready.
All: Reposition the small reflective rocks, not the large blocking ones, so that all four lasers around the room strike the central totem. It is solved by trial and error, and the layout randomises per instance.
Hard Mode: Activate the Challenge Banner before the fight (Veteran only; achievement: Telvanni Tormentor).
Tank: She targets you with a very wide, very long poison cone that tracks you. Face it away from the group and hold near the edge of the arena, with your back to the wall, to leave everyone else room.
All: If the Vomit Cone catches anyone other than the tank, that player uncontrollably spews poison in front of themselves for a few seconds. Stay clear of anyone this happens to.
All: At 70% and 35% health she fills the whole room with a poison effect. Everyone needs healing through it for a few seconds.
All: Take the synergy that appears after Poison Storm. It clears the poison and stuns the adds for a few seconds.
Dps: Focus the adds while they are stunned by the Time Stop synergy. They take extra damage during it, so it is worth saving an ultimate for this window.
Tank: Taunt the Peryite's Glory adds, the green blobs, as they spawn through the fight.
Dps: The Peryite's Glory adds should die to normal cleave and area damage. If the group's area damage is weak, focus them down directly rather than letting them drain the tank.
Dps: Hard Mode only. Adds during Poison Storm are fully invulnerable, rather than merely resistant, until the Time Stop synergy stuns them. That window is the only time to kill them, so save ultimates for it if needed.
Tank: Hard Mode only. Help control the Skeever summoned periodically, using crowd control such as a pull or a root. It locks onto a player (marked with a red rune) and cannot be taunted.
Healer: Hard Mode only. A red rune above your head means a Skeever is locked onto you. Kite it away to give the group time to kill it before it reaches you and applies Skeever Bite, a crippling debuff that dramatically increases the resource cost of all abilities.
Dps: Hard Mode only. A red rune above your head means a Skeever is locked onto you. Kite it away while others burn it; if it touches its target, it applies Skeever Bite, dramatically increasing all ability resource costs. CC and burn it immediately.