You progress by clearing to the North, then from the entrance back to the South and up. Final mob spawns back at the entrance again. Mobs do have knockback. Collect a torch from near the entry and use it to burn books and scroll traps with a fairly annoying AOE and knockback. Also scouts should disarm the egg shaped traps. If you approach slowly you can disarm the trap without triggering it. Once it is triggered it will take a few seconds to become targetable.
Icicle shaped mob
Ankhef and Zaza
We killed Zaza first, not sure if that is required. Once they are dead you head back to the zone in.
Best way is to pull by mezzing Zaza, the tank can rescue it off the mezzer if it doesn't stick. After mezzing immediately target Ankhef and kill him. Then return to Zaza to finish the fight.
Kill 3 of the 4 surrounding elements for it to absorb the last one and become attackable. Cold and crushing damage. Stuns about every 20-30 % and removes target for 15 secs.
a frozen thought
Key mob located at -223, 14, 31. The shard chest itself is in the room to the south (-211, 14, 124)
Spawned in the plaza upstairs by placing the pages from the rooms either side in the clicky at -194, 14, 79. You may have to click on the void to close it after Arcanus is dead.
Note: Arcanus spawns adds that will heal him. When the adds spawn burn them quickly and return to killing Arcanus.
Shade of Miragul
Spawns back at the zone in. Mental and crushing damage
Has AoE, farther you are, more damaging it is. He also knocksback people and slows them.
If everyone in the group stands on his toes he burns down pretty fast. If you get knocked back
just return to standing on his toes. Closer the better.