Sennarth is the fourth boss in the Vault of the Incarnates. This encounter revolves around having to survive the boss' attempts to pull players off the ledge or encase them in webs before reaching the final platform. The final platform itself is a race against time to defeat the boss before the raid is overwhelmed. 

This boss notably drops Tier Set tokens for the leg armor slot. Sennarth's loot has the following item levels: 376 (LFR), 389 (Normal), 402 (Heroic), 415 (Mythic). 

Tactics

Phase 1

• Try to be spread on the right side of the room and move left away from icy ground.

• Tank swap on around 5-7 stacks of Web Blast.

• Chilling Blast - spread out to let debuff expire.

• Sticky webbing puddles - only stand in them when the Gossamer Burst cast is about finished.

• If anyone gets webbed, remove by killing Caustic Spiderling nearby.

• As the boss moves up a flatform, be aware of chilling blast and then gossamer burst being cast fairly quickly.

• At the top of each ramp there is a small wall of rock that can help to prevent sliding off.

• Add - Frostbreath Arachnid (one per platform) - should be tanked near the right side of the boss, faced away from melee.  Boss will move to next platform when dead.

Phase 2

• Frost storm (Apex of Ice),  once everyone is on 4th platform, interrupt.

• Start tanking at the back of the platform, where she arrives.

• Chilling blast will drop puddles - drop at edges.

• Those with Suffocating Webs should stand just in front of the tanks (between boss and tanks).

Heroic

• Those webbed will be stunned for 30 seconds - spiderlings must die on top of them to release them.