Oathsworn Pit

Field of Blades

All: Ice spikes cover the ground. Do not stand in them.

Blood Adds

Dps: Small blood adds spawn and merge as they move. Kill them without taunting; they die quickly on their own.

Cone Slash

Tank: A frontal cone slash for heavy damage. Keep her faced away from the group.

Charge

All: She charges the tank's location. Be aware of the incoming hit and stay clear if you are not the tank.

Keep Them Apart

Tank: Rethelros (ranged) and Malthil (his wolf) empower each other when close together. Tank Malthil well away from the archer, who can be held at range.

Directed Volley

All: Damaging circles appear under random players and must be kited away. Standing in one is highly damaging.

Bear Trap

All: He scatters small traps. Stepping on one roots you for a long time, which is close to a death sentence. Watch the ground.

Protective Totem

Dps: A totem tethers to both enemies and reduces their damage taken. Kill it first to restore full damage.

Cinder Shot

All: A fiery line forms between Rethelros and three players. Do not stack with others when it fires, block the shot, and move away quickly, since it leaves a small bonfire at each target's location.

Malthil Chasing

All: Malthil occasionally loses aggro and chases a DPS or the healer. Run rather than stand and fight him; his enraged bite has long reach.

Cinder Shot on Everyone (Hard Mode)

All: Cinder Shot targets all four players at once instead of three. Block every one, and keep your spacing even more carefully.

Barbed Rain

All: Red circles rain onto the ground at random. Do not stand in them.

Spirit of Conquest

Dps: Ghosts spawn and try to claim braziers, changing their fire color to heal the boss if they reach one. Kill them with area damage, or light a brazier that has a red circle above it to instantly kill the ghost heading there.

Spectral Archer

Dps: They fire damaging fireballs at the group. Kill them as a priority before they overwhelm you.

Retrieve Axe

All: The Construct extends an arm to grab an axe from one of the arena corners. This deals heavy damage, so keep the boss centered and never stand between it and an axe.

Hurl Axe

All: It throws the retrieved axe at a random player. Dodge roll the instant it turns toward you and a red path appears; this attack is highly damaging.

Angry Inferno

All: A frontal fire cone. It can also clip other players if the boss turns mid-cast to grab or throw an axe, so do not stand near its front even if you are not the target.

Cindermoth

Dps: Cindermoths target a player and detonate on arrival. Kill them before they reach you, especially near an explosive barrel.

Explosive Barrels

All: Barrels around the arena explode on contact with fire and leave a permanent fire area. Watch where you fight relative to them.

Heat Blast (Anthelmir)

Dps: Anthelmir teleports and shields herself, then keeps casting Blasted Shards (block or dodge) at random players until the shield is destroyed or the Construct reaches 70% and they merge. You can ignore her and focus the Construct to 70% if the group is comfortable.

Merge (about 70%)

All: At 70% Construct health, Anthelmir and the Construct merge into a single boss for the rest of the fight. No new mechanics; there is just one target from here on.

Heavy Attack

Tank: His most damaging attack. Block it.

Meteor

All: A circle lands around each player's feet. Block it, or it stuns you.

Forge Summoning

Dps: He periodically runs to the room's forges and uses them to summon Flame Atronach allies. Left unchecked this overwhelms the group, so keep pace with add control.

Player Forge Counter

All: You can use the same forges to summon your own Cold-Flame Atronach allies, offsetting his summons. This is worth doing if his adds are piling up.

Emblazoned Strike

All: He charges an area effect and slams it into the ground, igniting the tiles it hits. On Hard Mode, plan ahead for where he will slam, since the ignited tiles are larger and stay lit until he ports away at 50% or dies.

Wildfire

All: Right after his slam, two random players receive a fire damage-over-time effect that ignites the tiles beneath them. Keep moving tile by tile and stay away from teammates. On Hard Mode, everyone except the tank receives it.

Twin Fires

Tank: A frontal fire cone aimed at you. Block it.

Molten Tile

All: You can dodge through ignited tiles if you must cross, but do not stand still on one.

Firestep

Tank: If the tank moves too far away, he teleports straight to them. Stay in reasonable range.

Meteor Call and Brimstone

All: Small eruptions are telegraphed as red plus-signs on the tiles beforehand. Remember which tiles were marked, since there is no warning left when they erupt. He can also ignite random tiles around the room (Brimstone) independently. On Hard Mode, Meteor Call's warning lines reach much further.

Awakened Fire

Tank: Fire Nixads throw flares at random players. Chain them to the boss so the group's area damage clears them.

Dps: Kill the Nixads once the tank has them stacked on the boss.

Furnace Side Bosses (about 50%)

All: At 50% he ignites the entire floor and the side-boss doors open. Head to the middle room. You fight one side boss on Normal, two on Veteran, or three at once on Hard Mode before Aradros returns; no new mechanics appear once they are down. You can also gather fire from the room's furnaces and bring it to the unfinished Atronach statue in the middle to build your own helper.

All Three Side Bosses (Hard Mode)

All: On Hard Mode all three side bosses (Faenalir, Nilborwen, Maerolor) arrive together instead of one or two. This is the hardest part of the fight, purely from managing several encounters' mechanics at once. Faenalir throws his shield (block or dodge it going out and coming back), summons chained magma-blob pillars that explode if you stray too far, and drops stalactites under each player. Nilborwen's Elemental Cross has a safe slice for the tank to stand in. Maerolor's Incineration can be tanked by a strong tank but a DPS or healer must avoid it, his Fire Wave travels in a line where he slams his hammer, and his Fire Slice cone should be interrupted the moment he casts it.