Ossirian the Unscarred Guide: Strategy, Abilities, Loot

• The boss is immune to taunts, so both tanks must be manually building more threat than the DPS.
• The boss must always be on top of a crystal. Each crystal will only give him 45 seconds of vulnerability. If he is not on top of a new crystal when the old one expires, he will regain his empowerment buff and deal enraged levels of damage.
• Tanks will absolutely need to have Free Action Potions to prevent being stunned by the boss's Enveloping Winds.

• The most dangerous part of the fight is when the group is moving between crystals. Watch the tanks carefully.
• Do not be in melee range of the boss to avoid his War Stomp.
• Druids should be decursing the Curse of Tongues from people.
• Avoid the tornadoes that move around the room.

• The most important part of the fight is moving the boss to crystals correctly, but the room is rather large and the crystals spawn far apart. Having a DPS stay mounted the whole fight to scout for crystals is a decent solution, if you think it will take multiple crystals to burn the boss down.
• Avoid the tornadoes that move around the room.
• Melee DPS should watch for when the boss casts War Stomp to move away.
• Mages should be decursing the Curse of Tongues from people.
• The boss is taunt immune, so start slowly to let tanks build aggro before going hard.

• Crystal management is 90% of the fight. Make sure you always know when and where you are taking the boss ahead of time.
• Avoid the tornadoes that move around the room.
• Make sure your tanks have Free Action Potions on hand to avoid the Enveloping Winds. Getting your main tank stunned for 10 seconds is an easy way to wipe, if it happens at the wrong time.

This fight is almost entirely dictated by the crystal spawns. The boss starts off with the Strength of Ossirian buff that makes him deal 200% more damage, which would normally cause him to murder your tanks. However, you can remove this temporarily by moving the boss on top of one of the crystals that spawn around the room. Moving the boss onto a crystal will make him vulnerable for 45 seconds, making him take 100% more damage from a random magic type as well as removing his buff. Once the 45 seconds is up, you will need to already be positioned to move him onto a new crystal, activating it when the boss is within range.

Managing the crystal spawns is the most important part of the fight since making a big move between crystals could easily result in a wipe, due to the boss killing your tank when he regains his buff. The best way to combat this is by having 1-2 melee DPS spend the entire fight running around the outside of the room on their mounts, activating any crystals that they come across. This will force new crystals to spawn in a random location, which means they could spawn in the middle of the room, closer to where the group is. You can effectively force crystals to spawn closer to the group, drastically reducing the travel time between crystals, thus making the fight much safer.

Your tanks will want to always have Free Action Potions on hand to use when the boss casts Enveloping Winds as this will let them avoid a 10 second stun. Once one tank uses one, they should let the other tank jump ahead in threat so they can swap. Besides this tank mechanic, the rest of the raid just needs to avoid the tornadoes, Mages and Druids can decurse people, and the melee can run away before War Stomp casts. As long as you are proactively managing your crystals well and planning out your movements, Ossirian should not prove to be too much trouble.