Algalon the Observer Strategy Guide – Ulduar (25)

Ulduar Algalon the Observer Raid Guide Featured Image

Algalon is a celestial being, a humanoid constellation. He serves as Azeroth’s guardian, monitoring the influence of the Old Gods and the progress of the mortal races. After assessing Azeroth, Algalon has concluded that the planet is too corrupt to continue in the Titans’ vision.

To solve the woes of the planet, Algalon will send Reply Code Omega to the titans, informing them of the corruption of Azeroth and dooming the planet. This would wipe out all life on the planet, allowing the titans to rebuild and retry.

This guide will offer a detailed, step-by-step tutorial on how to ensure that Algalon the Raid Destroyer has no tears to feed off of and that Reply Code Omega never reaches the titans.

Role Summaries

  • Make sure Collapsing Stars die with some delay between each death
  • The tank will take massive damage for the entire fight, make every cast count
  • Every 45 seconds the tanks will have to rotate, make sure you are ready to keep the new tank alive!
  • Every 45 seconds phase-punch-teleport will necessitate a tank swap, make sure you are ready to grab the boss
  • During big-bang one tank will need to remain outside of the black-hole-shift
    • Use a defensive if you are on the outside
  • Off-tanks should be ready to grab Living Constellations off of healers, taking them into the nearest black-hole-shift


Algalon deals heavy Physical damage to his current target and anyone within 5 yards of them. This is a significant amount of extra tank damage, on top of already very high tank damage. Healers will need to be on their toes at all times!

Every 15 seconds, Algalon deals moderate damage to his current target, applying one stack of phase-punch-damage to them. At 5 stacks they will receive the debuff phase-punch-teleport and be phased out for 10 seconds. An off-tank will need to quickly grab threat and pick up the pieces. These shifts will happen roughly every 45 seconds, necessitating regular tank swaps.

Algalon will mark up to three targets with a red void zone. After a delay, a meteor will crash into that location, dealing massive damage on impact, and reduced damage based on distance to everyone in the raid. Players will need to get as far away from the marked area as possible to take the minimum damage possible.

Every 90 seconds Algalon will channel big-bang for 8 seconds. After 8 seconds, anyone in the arena will take massive Physical damage. This damage can be avoided by phasing out of the arena by entering a black-hole-shift. Inside the black-hole-damage, players will be attacked by dark-matter, as well as taking Arcane damage every second.

The tank will need to stay behind, otherwise Algalon will enrage. This will require the tank to have some kind of damage reduction, such as Shield Wall or Pain Suppression.

Players will want to make sure they enter the black-hole-shift at the last possible second, giving them as much time as possible to DPS Algalon, and as little time as possible within the black-hole-shift. Once big-bang has finished casting, everyone will be returned to the arena from the black-hole-shifts.

This is Algalons enrage mechanic, dealing 6 digits of death to everyone in the raid. He will cast this 6 minutes after the fight starts, or if everyone is phased out.

Raid Composition & Preparation

This fight has no specific class or spec requirements, and as long as your group can out-heal the damage you should be able to pull through.

You will want 3-7 Healers for this fight, with no particular style of healing being more valuable.

There are no strict requirements for DPS classes or specs here, you simply want a combination of good raid buffs and debuffs, as well as the best players you can muster.

You will need at least 2 well-geared tanks for this fight, to taunt swap during phase-punch-teleport.

Accessing the Planetarium

To reach Algalon you will need to have obtained the Celestial Planetarium Key. To achieve this you will need to beat the Iron Assembly on either Medium or Hard Mode. This will cause the Archivum Data Disc to drop, starting the quest for the key.

algalon console 3

The Archivum Data Disc directs players to the Archivum, the room directly behind the Iron Assembly. Once in there, players can interact with the console, offering a follow-up from Prospector Loren, The Celestial Planetarium. This directs players to the Celestial Planetarium, which is currently locked.

After you turn in The Celestial Planetarium, players will be able to pick up the quests Freya’s Sigil, Hodir’s Sigil, Mimiron’s Sigil, and Thorim’s Sigil. Each of these quests requires the raid to beat the corresponding Keeper on Hard Mode. Some of these are going to be easier than others, but they all pose their own challenge.

Once you have completed all four quests, you can return to the Archivum Console to receive your Celestial Planetarium Key, and face what may be the most difficult fight in the game up until this point.

algalon door 2 1

The Pull

Once the raid has entered the Celestial Planetarium, a brief dialogue will ensue. Algalon will eventually appear, transforming the arena and attacking. Because he is not initially available to attack before combat begins, tanks will need to make sure they do everything possible to grab the initial threat before anyone takes a hit.

algalon raid guide basic positioning

The Fight

Phase 1

Algalon swings fast and hits hard, dealing constant hits with both a main-hand and an off-hand weapon. In addition to his basic swings, he will also regularly use quantum-strike on the tank, dealing massive Physical damage to everyone within 5 yards of them. Every 15 seconds, Algalon will hit the tank with one stack of phase-punch-damage. After reaching 5 stacks, the tank will be phased out for 10 seconds. This causes Algalon to swap target to the player second highest on threat.

This forced tank swap will require your off-tank to be very mindful of their threat, and your Healers will need to be fully aware of how many stacks so that they can quickly swap to healing the new tank. This will happen across the entire fight, so make sure everyone is paying attention!

Alongside phase-punch-damage, Algalon will also summon groups of collapsing-stars. These will slowly die on their own accord, losing 1% health every second. When they die they will cast black-hole-explosion, dealing heavy Shadow damage to everyone in the raid and leaving a black-hole-shift in their wake. It is important that a handful of ranged DPS are assigned to the Collapsing Stars, as if they are left to die on their own they will easily sync black-hole-explosion, wiping the raid instantly. Raids will instead want to stagger their deaths, giving the raid enough time to be back to full health before the next one dies.

Algalon will also cast cosmic-smash on a random raid member, creating a red void zone at their feet. After a small delay, a Meteor will crash into the red area, dealing massive damage on impact. This damage will also hit everyone in the raid, scaling based on their distance. This makes it vital that players get as far away as possible from the meteor to minimize the damage taken in an already damage-heavy fight.

Around one minute into the fight, Algalon will spawn three living-constellations that will attack whoever is highest on threat for them. This typically means that Healers will be focused first, and an off-tank will want to pull them off the Healer. These adds attack with arcane-barrage, dealing moderate Arcane damage to a single target. This is possible to heal through, but that healing could be more valuable elsewhere. Instead, you can kill a Living Constellation by dragging it through the black-hole-shifts left behind when Collapsing Stars die. Simply position a black-hole-shift between yourself and the Living Constellation and create distance.

Every 90 seconds, Algalon will cast big-bang. This 8-second cast deals colossal Physical damage to everyone that is not currently in a black-hole-shift. To counter this, everyone in the raid except the main-tank will need to quickly get into a black-hole-shift. The main-tank will need to stay out of the black-hole-shifts, as Algalon will enrage if no one is left to fight him. To survive the tank will need to utilize defensive cooldowns that reduce Physical damage taken, such as Shield Wall or Pain Suppression.

Players inside the black-hole-damages will take a small amount of Arcane damage every second, while also being attacked by Dark Matter. Dark Matter has no special abilities, only attacking players. Even though the damage inside black-hole-damages is fairly low, players will still want to enter them towards the end of big-bangs cast, minimizing the damage they take from the black-hole-damage and maximizing the time spent DPSing Algalon. After big-bang hits, everyone will be returned to the fight.

Phase 2

When Algalon reaches 20% Health, Phase 2 begins. Collapsing Stars and Living Constellations will no longer spawn. 4 black-hole-shifts will appear around the arena, constantly spawning Dark Matter. Algalon will still cast big-bang, requiring players to hide in the black-hole-shifts, but the tank may have a more difficult time staying alive while swarmed by Dark Matter.

Ideally, this Phase should start very soon after Algalon casts big-bang. This gives the raid the best possible window to burn the final 20% health down before the next cast, which could potentially wipe the raid. If you are not close to the 6-minute enrage timer, consider delaying for this.

Here are some of the main things that can typically go wrong in this fight:

  • The tank dies in one of 5 different ways
  • Living Constellations are allowed to freely DPS Healers
  • Collapsing Stars are ignored, syncing their black-hole-explosions together
  • Players do not avoid cosmic-smash effectively, taking significantly more damage than needed
  • Players fail to hide in black-hole-shifts for big-bang
  • The raid does not have enough DPS to beat the enrage timer


  • He Feeds On Your Tears
    • Defeat Algalon without anyone dying to him at any point this week. This is going to be a very difficult one, similar to Immortal from Naxxramas, but on a significantly harder fight.
  • Observed
    • Kill Algalon. Easy. This grants you the title the Astral Walker, one of my personal favorites.
  • Supermassive
    • Close 3 black-hole-shifts within 10 seconds before defeating Algalon. This requires some planning. Ideally, you should try to kill 3 Collapsing Stars close to each other, and have an off-tank stack 3 Living Constellations before dragging them through the black-hole-shifts. Warlocks can be a good choice for this, using Demonic Circle to teleport behind a black-hole-shift after getting aggro.

Congratulations on defeating Algalon. If you made it this far, you should be proud of both yourself and your guild’s accomplishment!


About the Author


I love MMOs of all shades, especially the nitty gritty numbers parts of them. You might recognize me from the Shadow Priest discord, otherwise I play a little bit of everything, especially games with support roles available.
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