For ten thousand years, the Queen's Court has never failed to enforce the word of Azshara. Now, the queen's most powerful servants stand ready to fulfill her final decree.
There are two bosses in this encounter: Silivaz the Zealous (Melee), and Pashmar the Fanatical (Ranged).
Generally, you will want Melee DPS to focus on Silivaz and Ranged DPS on Pashmar as Pashmar's abilities force players to move away from her.
These bosses do not share health and will need to be killed at a similar time. When one of them reaches 1 health it will attempt to cast 
Desperate Measures, which if completed will heal the boss back to 30%. Get both bosses to 1 health to interrupt the cast and end the encounter.
The bosses must be tanked at least 21 yards away from each other as if they are any closer they will gain the 
Separation of Power buff reducing their damage taken by 99%.
Queen Azshara will also be watching and forcing the raid to fulfil her Decrees throughout the encounter.
Silivaz the Zealous
Commander's Fury - Each successful hit increases their attack speed by 8%. This effect stacks on the boss, however this is not the tank swap of the encounter.
Frenetic Charge - The boss will select a non-tank player and after 6 seconds charge at them dealing heavy Frost damage which can be split with all targets within 8 yards. After this the marked player will leave behind a 
Mighty Rupture pool. This player will want to move to the edge of the room and ideally away from Pashmar to avoid the damage reduction on the bosses.
Zealous Eruption - When Silivaz reaches 100 energy he will spawn a barrier around him and deal heavy frost damage to all players not within the barrier for 10 seconds.
Pashmar the Fanatical
Pashmar's Touch - Each successful hit applies 1 stack of this debuff. At 10 stacks the target will be mind controlled. This is the main tank swap ability of the encounter.
Fanatical Verdict - Random non-tank players will receive this debuff throughout the encounter. This debuff will cause them to deal heavy Nature damage to anyone within 6 yards of them when it expires.
Violent Outburst - When Pashmar reaches 100 energy she will begin to cast this spell. This deals raid wide damage however the damage you take is based on your distance from her. The minimum damage taken appears to be around 35 yards away.
Potent Spark - When this is cast 3 Potent Spark orbs will spawn in set areas around the room. They will slowly lose health over time and when they die, they will deal a large amount of Nature damage to the raid. You will want to focus one orb as soon as they spawn and shortly after kill the second. The final orb should be left to decay on its own.
[Heroic] When a Potent Spark dies the raid will receive a debuff for 5 seconds increasing the damage taken from Potent Spark by 100%. This will force you to deal with them as described above rather than just letting them all die at the same time.
Queen Azshara's Decrees
Queen Azshara will cast decrees on players every 60 seconds, and they last 30 seconds each.
[Heroic] This will be cast every 45 seconds which leaves 15 seconds of downtime between each Decree.
There are 5 Decrees in total and these are cast in a set order: 
Form Ranks > 
Repeat Performance > 
Stand Alone > 
Deferred Sentence > 
Obey or Suffer
Once all 5 have been cast the cycle will repeat.
Form Ranks - Sets of Arcane zones will spawn in the middle of the room, after 5 seconds they will explode and there will be a 5 second break before the next set spawns. There will be 3 sets in total per Decree. These need to be soaked by players else they will deal heavy raid wide Arcane damage.
Please note: Other mechanics can occur during this Decree such as Zealous Eruption or Violent Outburst, for this reason it is recommended to tank Silivaz in the middle of the room, and Pashmar towards the outer edge.
Repeat Performance - Casting the same ability twice in a row will silence you for 2 seconds. It is worth noting that all spells count towards this, including interrupts.
Stand Alone - You will have a 5 yard circle projected around your character, if any other players are within it, all players will take Frost damage.
Please note: Other mechanics can occur during this Decree which force you to stack such as Frenetic Charge or Zealous Eruption.
Deferred Sentence - You will gain a stack of this debuff for each second you are standing still. Moving will reset the stacks and deal damage to you based on the amount of stacks that you had. Ideally you should reset it at 3/4 stacks.
Obey or Suffer - Any damage taken during this Decree will give the player the 
Suffering debuff which will absorb all healing for 5 seconds. After this debuff has expired it can not be triggered again for 5 seconds allowing you to be healed.
Please note: Other mechanics can happen during this Decree such as Potent Spark.
Mythic
Queen Azshara's Decrees will happen every 30 seconds which leaves no downtime between each Decree.
Sphere of Influence - Each Decree Activated will create a Sphere of Influence zone around the flag associated with the Decree. Inside this area the power of the Decree is amplified and players will take a large amount of Shadow damage.
Form Ranks - This Decree has been modified to spawn on the outside of the room rather than the middle and there are 5 Arcane zones to spawn (up from 3).
Keep the bosses 21 yards apart from each other
When tanking Pashmar during Zealous Eruption utilise defensives
Do not reach 10 stacks of Pashmar's Touch
You can pre-place your 
transcendence in the middle of the room, and 
Chi Torpedo for more efficient tank swaps
During Repeat Performance as the monk GCD is 1 second, adopt a rotation which is Blackout Strike > Something > Something else to never get silenced.
You can 
Infernal Strike to the bosses for more efficient tank swaps
During Repeat Performance you can use Throw Glaive between every cast and never be silenced
You can 
Divine Steed to the bosses for more efficient tank swaps
You can place 
Blessing of Spellward on your co-tank (or yourself) to survive the Zealous Eruption (if required)
During Repeat Performance you can use spells such as 
Contemplation or 
Rebuke if you need to cast two of the same spell in a row
During the Obey or Suffer Decree avoid wasting 
Light of the Protector whilst your healing is absorbed
[Untested] During the Obey of Suffer Decree the Suffering debuff which negates all healing has a potential to be negated with Blessing of Spellwarding / 
Divine Shield.
You can 
Heroic Leap to the bosses for more efficient tank swaps
During Repeat Performance you can use spells such as 
Heroic Throw or 
Pummel if you need to cast two of the same spell in a row
You can 
Wild Charge to the bosses for more efficient tank swaps
Stampeding Roar is useful to help the raid move inside of the Zealous Eruption
During Repeat Performance you can use Swipe between casts and never be silenced
You can 
Wraith Walk to the bosses for more efficient tank swaps
During Repeat Performance you can use 
Blood Boil between casts of 
Heart Strike and never be silenced
During the Obey or Suffer Decree avoid wasting 
Death Strike whilst your healing is absorbed
[Untested] During the Obey of Suffer Decree the Suffering debuff which negates all healing has a potential to be negated with 
Anti-Magic Shell.