So here's the secret to that final boss!

Boss, Totem, mobs are the phases


Boss Phase

Kill it! Faster the better also on mini bosses save resources and build up ult. Don't kill till you have an ult for you need an ult for the next phase.

Totem

So the totem actually doesn't drain everyone at once. It reaches toward the nearest person first. Ideally the tank should take the burn while healer should be 2nd nearest and dd should finish off. Also really important for everyone to attack it to make up for damage and a possible missing dd (bad luck if someone is unarmed mode). Lastly make sure as a healer you use cleanse from alliance war line first ( why cause it migrate some loss for 6 secs)

Mobs

Stamina and magicaka are best to bring here. Magicka dd for aoe while stamina dd focus on archers. Either way they got to die fast.