The ancient stoneborn generals, Kaal and Grashaal, have hounded the Prince Renathal's rebellion at every turn. Once they were General Draven's apprentice and mentor; now their strength, strategy, and soldiers have been unleashed against him and any who would defy the Sire's will.
Utilise the 
Stone Breaker's Combo to remove bleeds gained throughout the encounter.
Stone Breaker's Combo is cast on a non-tank raid member. If they are not near the boss, go to them if you need to clear your debuffs.
Phase 1+2: One tank on boss, one tank on adds.
Phase 1+2: Swap on 2 stacks of 
Serrated Tear or 
Stone Fist
Phase 2: Stone Fist knocks you back, do not be near an edge. You can fall off!
Phase 3: When your tanking partner is clearing their bleeds. Be ready to use defensive cooldowns as you will likely be tanking both bosses for a short period of time.
Black Ox Statue is useful to prevent adds from hitting other raid members before you generate threat on it.
When you are planning to remove your bleeds with Stone Breaker's Combo, have 
Celestial Brew active to ensure your health situation does not become bad.
Remember to 
Touch of Death the adds, you will get multiple uses of it during the encounter.
Place 
Transcendence on the boss platform and be ready to use it just in case you get knocked off.
Help funnel 
Anima Orbs into Renethal with 
Infernal Strike.
You can use Infernal Strike to counter the knockback from 
Shattering Blast (if you are not in position with the raid).
If you use 
Blessing of Spellwarding or 
Divine Shield on Crystalise, you will not get stunned.
You can soak Reverberating Eruption multiple times in a row with Blessing of Spellwarding or Divine Shield.
Serrated Swipe is blockable.
Intervene can be used on your co-tank to mitigate some of their damage taken whilst you are not tanking.
Intervene can be used on the target from 
Ravenous Feast to take all of the damage.
You can deflect the 
Wicked Laceration bleed (from 
Wicked Blade) with 
Spell Reflection.
Help funnel Anima Orbs into Renethal with 
Heroic Leap.
You can use Heroic Leap to counter the knockback from Shattering Blast (if you are not in position with the raid).
Rallying Cry is great to use during Pulverizing Meteor (from the Stone Breaker's Combo).
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If you use 
Anti-Magic Shell on 
Crystalize, you will not get stunned.
Once you have been Crystalize by Stone Breaker's Combo you can break this stun with 
Icebound Fortitude. Very useful during Phase 3 where you may be tanking a boss at the same time.
Death's Advance can negate the knockback from Shattering Blast.
Anti-Magic Zone is great to use during Pulverizing Meteor (from the Stone Breaker's Combo).
During this fight you will fight two bosses (one at a time), and adds will spawn throughout the encounter. The adds are always the priority on this encounter.
Whilst you are fighting one boss, the other will be airborne and take 95% less damage. They will still cast mechanics on the raid.
During this phase General Grashaal is airborne and will still cast 
Stone Spike (small Physical damage hit on random players which slows) and Stone Breaker's Combo. Refer to the Phase 2 section for more information on Stone Breaker's Combo.
Serrated Swipe - This is the main tank mechanic of General Kaal, where every ~20 seconds this will be cast on the active tank and a stack of Serrated Tear is applied. This bleed is permanent and can only be removed by Stone Breaker's Combo.
Heart Rend - These debuffs will be applied to several players throughout the phase. They will deal a low amount of Shadow damage every 3 seconds, however when the debuff is removed (dispel) or expires, the player will receive 
Heart Hemorrhage which deals a high amount of Shadow damage over 6 seconds.
Wicked Blade - 2 non-tank players will be targeted and General Kaal will throw a blade which applies a bleed around the targets hit and to all players in the path of the blade. When players are hit they will receive the Wicked Laceration which is another permanent bleed that can only be removed by Stone Breaker's Combo.
Ensure locations have been set up ahead of time for players to manage this mechanic.
General Kaal will also spawn Stone Legion Goliaths throughout the encounter.
Stone Legion Goliath
This add will spawn roughly every ~minute in Phase 1 and 2, and during Intermissions only 1 will spawn regardless of the length. It will need to be tanked by the tank who is not actively tanking the boss.
Whilst they are alive they will periodically gain stacks of 
Ravenous Hunger which increases the damage it deals by 60% per stack (75% on Heroic),
It will also pick a random non-tank player and leap to them casting Ravenous Feast. The player targeted will be stunned them for 4 seconds, and have a very large amount of Phsyical damage to them over 4 seconds.
When it reaches 20% health it will channel 
Soultaint Effigy which reduces the healing all players receive by 10%. This effect stacks every second.
When this add reaches 20% health kill it ASAP.
When the active boss reaches 50% health, they will become immune to further damage and Anima Orbs will spawn in the encounter area when any add has been killed.
The intermission will also pause any add spawn timers and spawn a single Stone Legion Goliath and multiple Stone Legion Commandos will fly overhead. The bosses will still do all of their main phase abilities during these intermissions.
Stone Legion Commando
These adds will be flying above the encounter area and should be killed by ranged DPS players. They will cast 
Cluster Bombardment on player locations, if any player is hit by this they will take a moderate amount of Shadow damage.
Anima Orbs
When adds die after the boss has reached 50% health it will spawn an Anima Orb. When collected this gives the player Anima Infection which allows them to deliver the Anima to Prince Renathal who is at the back of the encounter area. Once delivered 30% of his mana will be restored.
Once Prince Renathal is at 100% mana, he will cast Shattering Blast. This will deal a small amount of raid wide Shadow damage, all players will be knocked back and Phase 2 will begin.
During this phase General Kaal is airborne and will still cast Wicked Blade and 
Ricocheting Shuriken (small Physical damage on random players which will bounce to three nearby players). Refer to the Phase 1 section for more information on Wicked Blade.
Stone Breaker's Combo - This is a key mechanic of the encounter which allows you to remove the bleeds in the encounter. This comes in three parts.
1) A random player will be Crystalized, this is a channelled spell and at the end of the channel 
Crystalline Burst will trigger on all players within 8 yards.
2) Anyone with Crystalline Burst will be stunned for 4 seconds, have all of their Bleeds removed and take a moderate amount of Nature damage.
3) As Crystalline Burst starts a 
Pulverizing Meteor will spawn in that location dealing a very large amount of Nature damage. This damage is split between all players in the area.
Due to how this mechanic prevents you from doing anything whilst stunned it is advisable to only have players with bleeds get hit by the initial hit. This includes the tank on Kaal.
Stone Fist - This is the main tank mechanic of General Grashaal. When cast any player in a small cone area in front of General Grashaal will take a large amount of Physical damage and be knocked back. This will also leave a stacking debuff on the player increasing their damage taken by 100% for 40 seconds.
Reverberating Eruption - A non-tank player will be targeted by this and after 5 seconds the location they are in will now become Unstable Ground. Any existing Unstable Ground will erupt with 
Echoing Annihilation. If Echoing Annihilation is not soaked, then it will trigger raid wide damage via 
Echoing Blast. Additionally, any player hit by any of these will get the 
Reverberating Vulnerability debuff, preventing them from soaking multiple.
[Heroic] Reverberating Vulnerability now has a 45 second duration (up from 6 seconds), meaning that you cannot soak them each time Reverberating Eruption occurs.
Ensure every patch of Unstable Ground has a player soaking it every cast. Heroic Have a set rotation of people to ensure people with Reverberating Vulnerability are not soaking.
Seismic Upheaval - Player locations will be marked and detonate shortly after. Any player within 5 yards of these locations will take a moderate burst of Physical damage.
As with Phase 1, when Prince Renathal is at 100% mana, he will cast Shattering Blast. This will deal a small amount of raid wide Shadow damage, all players will be knocked back and Phase 3 will begin.
You will now be fighting both bosses. When one boss dies the other will receive 
Soldier's Oath which will increase their damage by 200%. Ensure both bosses are low when you're going for the kill to prevent having to fight an enraged boss for too long!
As both bosses are active at the same time, this also means that both tanks mechanics will be happening.
There will be no adds during this phase, so the importance here is to ensure that mechanics are handled correctly.
For the tanks, you will want to swap based on the Stone Fist debuff stacks and use the time tanking Grashaal to clear your Serrated Tear stacks.
There are changes to various mechanics on Mythic which will be detailed below.
Heart Rend - This now applies Heart Hemorrhage to the player that dispels the debuff.
Tip: It is possible to mass dispel these meaning that healing can be focused on one player
Stone Legion Skirmishers are new adds that spawn frequently. These adds spawn in sets of three (3) and when they reach 30% health they will become rooted and channel 
Stonegale Effigy until killed. This will attempt to push players off the platform. Kill them before you fall off!
The Stone Legion Goliaths also have their Soultaint Effigy buffed to reduce healing received by 20% per stack (up from 10%).
Stone Legion Commandos will now have an absorb shield on them when they reach 20% health. Stone Shell Detonation lasts for 6 seconds, and if it is not removed it will deal a large burst of Shadow damage to players within 40 yards.
This section will be updated once a strategy has been devised for Mythic on live servers
General Kaal Swing Timer: 1s (Curse of Weakness 1.2s)
General Grashaal Swing Timer: 2s (Curse of Weakness 2.4s)
Black Ox Statue is useful to prevent adds from hitting other raid members before you generate threat on it.
When you are planning to remove your bleeds with Stone Breaker's Combo, have Celestial Brew active to ensure your health situation does not become bad.
Remember to Touch of Death the adds, you will get multiple uses of it during the encounter.
Place Transcendence on the boss platform and be ready to use it just in case you get knocked off.
Help funnel Anima Orbs into Renethal with Infernal Strike.
You can use Infernal Strike to counter the knockback from Shattering Blast (if you are not in position with the raid).
If you use Blessing of Spellwarding or Divine Shield on Crystalise, you will not get stunned.
You can soak Reverberating Eruption multiple times in a row with Blessing of Spellwarding or Divine Shield.
Serrated Swipe is blockable.
Intervene can be used on your co-tank to mitigate some of their damage taken whilst you are not tanking.
Intervene can be used on the target from Ravenous Feast to take all of the damage.
You can deflect the Wicked Laceration bleed (from Wicked Blade) with Spell Reflection.
Help funnel Anima Orbs into Renethal with Heroic Leap.
You can use Heroic Leap to counter the knockback from Shattering Blast (if you are not in position with the raid).
Rallying Cry is great to use during Pulverizing Meteor (from the Stone Breaker's Combo).
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If you use Anti-Magic Shell on Crystalize, you will not get stunned.
Once you have been Crystalize by Stone Breaker's Combo you can break this stun with Icebound Fortitude. Very useful during Phase 3 where you may be tanking a boss at the same time.
Death's Advance can negate the knockback from Shattering Blast.
Anti-Magic Zone is great to use during Pulverizing Meteor (from the Stone Breaker's Combo).