The Sixth Boss
Strategy
Ossirian is the final boss in AQ20. This boss begins the encounter under the effects of Strength of Ossirian, increasing his damage by 300%. In order to weaken him, you'll have to active different random crystals that appear near him, making him susceptible to a particular school of magic for 45 seconds. Ossirian will become weak to one of five schools of magic: Fire, Frost, Shadow, Nature, or Arcane, drastically increasing damage taken from these elements. You simplify this phase by having two melee classes repeatedly patrol the room and ping the location of the crystals on the mini-map until the boss is near death.
In addition, Ossirian cannot be taunted, so you should let your two tanks build threat manually, as they will have to tank swap after the main tank is stunned by Enveloping Winds for 10 seconds. It is a good idea to use Free Action Potions to avoid being stunned, but make sure to use these intelligently to prevent your offtank from losing too much threat.
Tornadoes will also randomly spawn throughout the room — do your best to dodge them and avoid taking unnecessary damage and a movement speed debuff. Ossirian will also use War Stomp during the fight to deal damage and knock back nearby players. This ability can be used to your advantage, as it can launch you towards far-off crystals!
Finally, you should prioritise decursing Curse of Tongues, which will affect random players.
