Yogg-Saron is the last regular boss in the Ulduar instance. He is an exceptionally complicated boss to defeat with three separate phases each requiring coordination, movement and skill from all players involved. The fight starts off against Sara who is a projection of Yogg-Saron, it then moves to a tentacle / brain phase, and then lastly against you need to fight Yogg-Sarons body.
Yogg-Saron 10 player raid 11,000,000 health
Yogg-Saron 25 player raid 44,000,000 health
Guardian of Yogg-Saron 10 player raid 220,000 health
Guardian of Yogg-Saron 25 player raid 950,000 health
Immortal Guardian 10 player raid 100,000 health
Immortal Guardian 25 player raid 500,000 health
Special Fight Mechanics
Sanity - For this encounter all players gain an additional character stat called Sanity. This shows up as a buff to all players and starts at 100. If at any point this buff reaches zero stacks you will become insane. Players can regain sanity points by standing in the green pillars of light around the edge of the room.
Insane If your sanity buff reaches zero you loose it and gain the debuff called Insane. Once you are insane you are mind controlled by Yogg-Saron until the encounter is over, even if you are killed. Therefore you should never battle rez an insane party member.
Additional Creatures (Adds) Abilities
Guardian of Yogg-Saron (Phase one only) These guardians are summoned in phase one and have two main abilities. They can cast dark volley which hits everyone in the raid for roughly 10,000 shadow damage and reduces healing done by 25% for 10 seconds. In addition they cast shadow nova when they are killed which deals a large amount of shadow damage to everyone.
Constrictor Tentacle (Phase two only) These tentacles attempt to grab and constrict anyone nearby. Once grabbed they squeeze the player for roughly 7,500 damage per second.
Corruptor Tentacle (Phase two only) These are caster based tentacles that have several abilities. The first is the ability to inflict the Black Plague on players which causes them to be stunned for 2 seconds at a time several times over its 30 second duration. Next up they can place a poison on a player that deals nature damage and drains mana, this lasts fro roughly 20 seconds. They can cast a curse of doom that lasts for 12 seconds and if it remains until the end of that time inflicts roughly 20,000 shadow damage. They can also make players apathetic reducing the targets attack, movement, and casting speed by 60%. All of these abilities can be removed from players as they are either magic, curse, disease of poison effects.
Crusher Tentacle (Phase two only) These tentacles continually attempt to channel Diminish Power which reduces all damage caused by roughly 20% to anyone in the room, this ability stacks from up to 4 tentacles. It can be interrupted by being hit by melee. Each time they are hit by melee though they gain a focused anger buff which stacks to 100. Each stack increases damage dealt and attack speed by 3%. If melee is in range while angered, the tentacles will attack them instead of channelling Diminish Power.
Influence Tentacle (Phase two in the Minds Eye only) These tentacles attack players but have not real special abilities other than reflecting damage back at attackers. 60% of the damage done to them is reflected back.
Immortal Guardian (Phase three only) These guardians are summoned in the third phase of the fight. And have several abilities, primarily though they hit exceptionally hard against tanks. Their melee hitting power directly relates to their health, so you need to burn them down quickly. They also have a drain life ability that heals them while hurting a player for 5 seconds. They can also be healed through Yogg-Sarons shadow beacon. Lastly Immortal Guardians can only be killed by Thorims Titanic Storm ability while at 1% health.
Yogg-Sarons Abilities as Sara Phase One
While Yogg-Saron appears as Sara in phase one you can not directly attack him. Instead you must destroy Guardians near him to hurt Sara and drop him down to start phase 2.
Saras Anger This is a buff places on a target and increases physical damage done by 12,000, however is deals roughly 12,000 shadow damage every 3 seconds. The buff lasts 12 seconds.
Saras Blessing Heals a target for roughly 30,000 health but also places a DOT on the target that deals 60,000 shadow damage over 20 seconds.
Saras Fervor This is a buff placed on a target that increases damage caused by 20% but increases damage taken by 100%. This buff lasts 15 seconds.
Yogg-Sarons Abilities Phase Two
Brain Link This ability targets two random raid members and links their brains. Both targets suffer 3,000 shadow damage and lose 2 sanity buffs every second that they spend further than 20 yards away from each other.
Shadowy Barrier This is an invulnerable shield that protects Yogg-Saron, rendering him immune from harm.
Death Ray This is an AOE blast that deals a huge amount of nature damage to anyone in it. The damage is roughly 20,000 nature damage per tick, and it ticks fast enough that if you are caught by it you are dead.
Malady of the Mind This ability deals roughly 5,000 shadow damage and causes the player to lose 3 stacks of sanity. In addition it causes you to run in terror for 4 seconds, if anyone is within 10 yards of you at the end of your terror it will be passed on to that player and start again.
Psychosis This attack his players with 5,000 shadow damage and causes them to lose a large amount of sanity, roughly 10% of their current sanity.
Yogg-Sarons Brains Abilities Phase Two
Induce Madness This is a 60 second cast ability that when finished will reduce any players that are in the brain room to zero driving them insane.
Lunatic Gaze This ability appears as a ghostly laughing skull. If your character is turned to face it they will suffer roughly 2,000 shadow damage and lose 2 sanity every second.
Yogg-Sarons Abilities Phase Three
Lunatic Gaze This ability inflicts roughly 5,000 shadow damage and removes 4 sanity each second for as long as you are facing Yogg-Saron. The spell lasts 4 seconds and is cast every 12 seconds.
Empowered Shadows This ability heals all friendly targets within 20 yards for roughly 750,000 health over 20 seconds.
Extinguish Life This ability is used 15 minutes after the encounter first start. When used it kills all players.
As you can see from the list of abilities the fight can be pretty complicated. However if you take each phase separately and realize it will take several attempts at each phase to learn it, you can get through it just fine.
Phase One Strategy
Phase one starts when you enter the room and engage Yogg-Sarons avatar Sara. From this point you have 15 minutes to get through all three phases and defeat Yogg-Saron. To get by phase one you must destroy Sara, however she is immune to all player damage. The only way to cause damage to her is to defeat a Guardian of Yogg-Saron within 15 yards of her so that the damage from its shadow nova damages her. It takes the damage from 8 shadow novas to defeat her.
To accomplish this the tank must hold Guardians near Sara while they are being DPSed down. However since they cause shadow damage with the nova to everyone nearby when they die, melee DPS must clear away from them when their health gets low and let ranged DPS finish them off. Guardians spawn in the room at an increasing rate the longer the phase goes on.
The difficulty with the fight is that while this is going on there are clouds floating around the room that players must avoid. Any cloud that is touched will cause the spawning of an additional Guardian. While it may be beneficial to spawn an extra guardian or two early if your groups DPS can handle them, it can lead to a very fast wipe if you cant.
The clouds spiral around the room in slow elliptical orbits. All players need to watch for them and avoid them. Plan ahead and look for places to stand that will be clear for a while. Once players get used to avoiding the clouds while dealing with the Guardians the phase becomes very simple.
Once you have killed the required 8 Guardians beside Sara you move on to phase two. If there are any additional Guardians up you will need to clear them up.
Phase Two Strategy
When phase two starts Yogg-Saron will appear in the center of the room encased in a protective shield. He is immune to direct damage in this phase. This phase centers around dealing with the three types of tenticals that can be spawned as well as taking down the shield by sending players into Yogg-Sarons brain room called the Minds Eye. The raid needs to be split into two groups at this point in the encounter, a group for the Minds Eye and a Tentacle group. In 10 player raids only 4 players are allowed to enter the portals and in 25 player raids 10 are allowed to enter.
The group that is going to deal with the Minds Eye needs to have some very good DPS and heals. Throughout the fight portals to the Yogg-Sarons Minds Eye will open throughout the room, when they do this assigned group needs to enter them quickly as Yogg-Saron will have started to cast his Induce Madness ability. The first portal opens roughly a minute after the phase starts and then additional portals open roughly 15 seconds after a group has come back from each brain phase.
Once the group enters they will see an illusion of people in the room. To dispel this illusion you must kill the Influence tentacles that they find while avoiding looking at the skulls that cast Lunatic Gaze. Once all of the tentacles have been defeated you can enter the brain room and start DPSing Yogg-Sarons brain. At the back of the braid norm there is a portal back to the regular room. Players need to leave enough time to reach the portal and get out before Induce Madness completes casting. Once they click on the portal they will appear back in the main room with the group. As you can tell this phase is very fast paced and hectic. You need to do enough damage quickly so that you only have to go into the Minds Eye about 3 times.
The players that are left to deal with the tentacles need to deal with the tentacles as quickly as they appear. If you let too many stack up the fight will quickly degenerate into a wipe.
Constrictor tentacles are the priority as they have low health and will not let a player go once they have one until either they or the player is dead. While Constrictor tentacles are not up melee should focus on corruptors and ranged on crushers. This way the melee constantly interrupts the corruptors casting and avoids letting the crushers get the damage buff. If you want to interrupt the crushers diminish power ability you can assign a tank to move in and out of range interrupting it whenever possible. If you get to many hits on the tentacle though it can single shot almost any player.
While dealing with the tentacles you need to also watch out for Yogg-Sarons cast abilities. If you are affected by the Brain Link you need to look for the player you are linked to and run towards them. If you see someone running in terror with Malady of the Mind you need to keep your distance. If you see a Death Ray, you need to avoid it. All pretty simple to do as long as you are paying attention.
Once the brain team has done enough damage to the brain you will enter phase three.
Phase Three Strategy
Once you enter this phase Yogg-Saron will be at roughly 30% health and the fight essentially becomes a DPS race. The main issues with this phase are the Immortal Guardians and Yogg-Sarons Lunatic Gaze.
To deal with the Immortal Guardians a tank needs to grab and hold them as they appear, which will be every 15 seconds. DPS needs to be assigned to burn them down quickly as their stacking damage buff is based off of their health, initially they do huge damage, but once low they do almost nothing. Players can not kill these guardians instead you must wait for Thorim to used his Titanic Storm to kill them. The adds need to be tanked more than 20 yards away from Yogg-Saron or when they are targeted and healed by Empowering Shadows he will be healed as well.
[protip]The Heal from Empowering Shadow occurs every 45 seconds so it can be watched for. It is best if either a warrior, hunter or rogue applies their debuffs to minimize any healing done just before it is cast.[/protip]
The other major issue is Yogg-Sarons Lunatic Gaze which deals a lot of raid damage as well as very quickly driving players insane. When used this will appear as purple cylinders of light in front of Yogg-Saron, when they appear everyone must face away from them or suffer their effects. They last for 4 seconds and are cast every 12 seconds. This means that players can time their appearance and suffer almost no ill effect. For anyone that is getting low on sanity, they should run towards a green cylinder of light to gain sanity back.
You have until the 15 minute point to defeat Yogg-Saron before he wipes the raid with his extinguish life ability. Remember though that this is time from your initial interaction with Sara way back in phase one.
If you get to phase three though, it shouldnt be that hard.
Good luck and enjoy one hell of a fun fight!