When Azeroth was young, Odyn traded his eye to Mueh'zala to peer into the Shadowlands. Vain Odyn was deceived, for the Jailer twisted the Eye to serve his own ends. The Eye's unwavering gaze allows the Jailer to see all that transpires within his domain--and perhaps others as well.
Use the chains (or blink style abilities) to avoid the 
Annihilating Glare beam.
[Heroic] Swap tanking based on your 
Assailing Lance stacks.
One tank takes each side for the intermission. Tank the Deathseeker Eyes at least 55 yards away from each other to prevent 
Shared Suffering.
Dump your 
Spreading Misery puddles to the side of the room.
In the last 33% of the boss be ready to use cooldowns when you are above 5 stacks of 
Immediate Extermination as you will receive10% reduced healing per stack.
The amount of damage taken by the raid from 
Deathlink is based on the total amount of HP you lose. Therefore if you use 
Celestial Brew before the hit you will either reduce the damage taken by the raid significantly or the raid will take 0 damage.
You are able to go through the Annihilating Glare by placing 
Transcendence down and teleporting through once the beam has passed its location.
The amount of damage taken by the raid from Deathlink is based on the total amount of HP you lose. Therefore you should use 
Fiery Brand and 
Demon Spikes to mitigate the damage taken by yourself and the raid.
The amount of damage taken by the raid from Deathlink is based on the total amount of HP you lose. Therefore you should ensure you are stood within your 
Consecration, have 
Shield of the Righteous active and potentially use 
Ardent Defender as well to mitigate the damage taken by yourself and the raid.
Divine Shield can be used to remove Immediate Extermination stacks during the final 33% of the encounter.
[Heroic/Mythic] 
Blessing of Protection can be used to remove stacks of Assailing Lance.
The amount of damage taken by the raid from Deathlink is based on the total amount of HP you lose. Therefore you should use 
Shield Wall and/or 
Ignore Pain to mitigate the damage taken by yourself and the raid.
[Normal] Nothing on this encounter can be blocked.
[Heroic/Mythic] Only melee swings from the adds and Assailing Lance can be blocked on this encounter.
Piercing Lens from the intermission eyes can be reflected with 
Spell Reflection.
The amount of damage taken by the raid from Deathlink is based on the total amount of HP you lose. Therefore you should use 
Barkskin or 
Survival Instincts to mitigate the damage taken by yourself and the raid.
Stampeding Roar has multiple good uses on this encounter. It can be used to help people move with 
Dragging Chains, move away from Annihilating Glare, or get into position for the intermissions.
The amount of damage taken by the raid from Deathlink is based on the total amount of HP you lose. Therefore you should use 
Rune Tap to mitigate the damage taken, also if you have pooled a good size 
Blood Shield this will either reduce the damage taken by the raid or if the shield is large enough the raid will take 0 damage.
You can run through the Annihilating Glare beam with Anti-Magic Shell and Death's Advance. (On Mythic you will need to add additional cooldowns such as Rune Tap and Icebound Fortitude).
This is a two-phase encounter with multiple intermission phases. You will fight against the Eye of the Jailer 3 times for 33% boss health per time. The final 33% of the fight will be a race against time as you will receive less and less healing to the point where you become unhealable from Immediate Extermination.
Throughout the fight, you will need to make good use of the space in the room. Whilst it is a large room, you will need to be mindful of not wasting good space in the room as puddles that spawn during the intermission are permanent, and you will need access to the Harpoons at either end to jump across the gap to avoid Annihilating Glare.
Piercing Lens - This is the replacement for the melee swing on this encounter. As the boss is an eye, it will aggressively look at you instead of hitting you.
Deathlink - This is the tankbuster of the encounter, and you will need to mitigate this as best you can. Damage that you take will be dealt to the raid.
You can dodge/parry this, which means 0 damage taken by the raid.
Fracture Soul - White zones will appear on the floor. Move out of these. If this hits you, you will be affected by Fractured Soul, which splits your Soul into 3, and you need to collect them by running into it. Whilst you have the Fractured Soul debuff, your damage/healing will be lowered by 30%, and you will be slowed by 20%.
Annihilating Glare - The boss will pick a position in the room and project a beam that will sweep across the entire room. You will need to avoid being hit by this beam as it will deal a large amount of Shadow damage to you, and if you survive, you will be knocked back. You can jump over the gap at the back of the room with the chains located at the end of the platform.
The boss will distinctly face towards a side would face one side, and it would always sweep across the platform first. For example, if the boss faced the left, the beam would sweep to the right and vice versa.
If you have a blink style ability such as 
Soulshape or 
Door of Shadows, you can ignore this mechanic and blink through the beam.
Deathseeker Eyes
Eye Bolt - During this phase, they will cast this spell on random players dealing a small burst of Shadow damage.
[Heroic] Stygian Abductors
Dragging Chains - The Abductor will target a player that it will throw chains on. This player will have a glowing area around them. Any players inside this area will be chained to the Abductor, and it will attempt to pull you off the platform. However, you can pull against the chain and pull the Abductor onto the platform!
Assailing Lance - Once the Abductor is on the platform, it will need to be tanked, and it will periodically apply a stacking bleed to the tank. You should tank this next to the boss and swap on 2 stacks of the bleed.
This phase begins once the boss has reached 66% or 33% health.
At the start of this phase, the boss will retreat, and two of the Deathseeker Eyes surrounding it will come down on either side of the platform. They must not be within 55 yards of each other as they will trigger Shared Suffering.
During this phase, the boss will continue to use Fracture Soul and will gain two new abilities:
Titanic Death Gaze - This is a large raid-wide AoE which is unavoidable. You have to heal through it and potentially assign cooldowns for it.
Desolation Beam - One non-tank player will be targeted with this and have a visible animation around them. After 6 seconds, the beam will be cast on that player. If any players are nearby, it will chain to them, dealing more damage (and if players are near that player, it will continue chaining and dealing more damage!)
Deathseeker Eyes
Piercing Lens - Similar to the boss in phase 1, this will be the equivalent of a melee swing on the tank.
Spreading Misery - Will be cast on players throughout the phase, and after 5 seconds, a 
Jailer's Misery puddle will be left on the ground. These puddles do not despawn and should be placed towards the edge of the room to maximise available space (you have 3 intermission phases, so many puddles will spawn!)
Slothful Corruption - This debuff will be applied to several players periodically. It will slow spell casting and ranged attack speed (as well as movement speed). Ranged DPS should be dispelled as a priority.
Dying Suffering - When an Eye dies, it will cast Suffering every 8 seconds until the other Eye has been defeated.
After two eyes have been defeated, the Eye of the Jailer will return going into Phase 1. If you have defeated all 4 Deathseeker Eyes, Phase 2 will begin.
The final 33%! This Phase will play similarly to Phase 1; however, during this phase, the boss will buff themselves with Immediate Extermination.
Immediate Extermination - In addition to the boss increasing their attack rate by 50%, every 6 seconds, a burst of unavoidable Shadow damage will be dealt to the raid and apply a stacking debuff reducing healing received by 10% per stack.
In addition to the new buff, the boss has gained it will also cast Desolation Beam from the Intermission.
Eye Bolt will no longer be cast as....there are no Deathseeker Eyes to cast it.
Eye of the Jailer / Deathseeker Eyes: Inconsistent "Swing" timers. Lowest observed was 2s.
Stygian Abductor Swing Timer: 2s (Curse of Weakness 2.4s)
The amount of damage taken by the raid from Deathlink is based on the total amount of HP you lose. Therefore if you use Celestial Brew before the hit you will either reduce the damage taken by the raid significantly or the raid will take 0 damage.
You are able to go through the Annihilating Glare by placing Transcendence down and teleporting through once the beam has passed its location.
The amount of damage taken by the raid from Deathlink is based on the total amount of HP you lose. Therefore you should use Fiery Brand and Demon Spikes to mitigate the damage taken by yourself and the raid.
The amount of damage taken by the raid from Deathlink is based on the total amount of HP you lose. Therefore you should ensure you are stood within your Consecration, have Shield of the Righteous active and potentially use Ardent Defender as well to mitigate the damage taken by yourself and the raid.
Divine Shield can be used to remove Immediate Extermination stacks during the final 33% of the encounter.
[Heroic/Mythic] Blessing of Protection can be used to remove stacks of Assailing Lance.
The amount of damage taken by the raid from Deathlink is based on the total amount of HP you lose. Therefore you should use Shield Wall and/or Ignore Pain to mitigate the damage taken by yourself and the raid.
[Normal] Nothing on this encounter can be blocked.
[Heroic/Mythic] Only melee swings from the adds and Assailing Lance can be blocked on this encounter.
Piercing Lens from the intermission eyes can be reflected with Spell Reflection.
The amount of damage taken by the raid from Deathlink is based on the total amount of HP you lose. Therefore you should use Barkskin or Survival Instincts to mitigate the damage taken by yourself and the raid.
Stampeding Roar has multiple good uses on this encounter. It can be used to help people move with Dragging Chains, move away from Annihilating Glare, or get into position for the intermissions.
The amount of damage taken by the raid from Deathlink is based on the total amount of HP you lose. Therefore you should use Rune Tap to mitigate the damage taken, also if you have pooled a good size Blood Shield this will either reduce the damage taken by the raid or if the shield is large enough the raid will take 0 damage.
You can run through the Annihilating Glare beam with Anti-Magic Shell and Death's Advance. (On Mythic you will need to add additional cooldowns such as Rune Tap and Icebound Fortitude).