Lore:
So we’re taking on Arthas and the Blue Dragonflight and…wait…what’s that? There’s an Old God here too? With mouths everywhere and cultists running around killing everybody’s armies?
Well, whatever. We’ve banished one Old God, so it’s no big…wait. Yogg’Saron?! As in…Saronite?! As in the armor we’re all wearing is made out of his dried blood. Ewwwwwwwwwwwwww!
Degree of Difficulty: Hard
There’s a ton of trash, and none of it is really worth talking about. Just know going in that Ulduar is an old school instance that will likely take you several hours to crawl through, and all those hours will be filled with trash.
As for bosses, here’s a brief look:
Flame Leviathan: Unique in that you will fight this tank entirely as vehicles. He’ll charge one vehicle, and the others DPS it down.
Ignis: A giant with lots of ads and all kinds of fire damage (he’s skippable)
Razorscale: A proto-drake who also shoots fire everywhere and has adds.
XT-002 Deconstructor: A robot that just wants to play
The Assembly of Iron: Steelbreaker (a giant), Brundir (an iron dwarf), and Molgeim (a vykrul) who all get progressively stronger as you kill the others. Killing Steelbreaker last engages the hardmode of this fight.
Kologarn: Is a construct whose arms have to be knocked off.
Auriaya: A Titan Watcher that is sort of optional and has lots of adds.
Mimiron: A clockwork gnome who fights in four different vehicles throughout the fight. The Leviathan, the Antipersonnell Cannon, the Aerial Command Unit, and the V-07-TR-0n. All fights require massive healing, pushing the red button before the fight initiates hardmode. Mimiron has a small chance to drop his head (a mount).
Freya: A Titan watcher who has a ton of adds and AoE.
Thorim: A Titan watcher with lots of adds (see a pattern yet?) and a bunch of lighting damage.
Hodir: A Titan watcher with frost damages that can freeze party members and adds (that actually help you if you free them!)
General Vezax: A faceless and the second to last boss of the instance. Drops a lot of AoE including Saronite crystals that will kill you (but restore your mana) and stack forever.
Yogg-Saron: The Old God, who fights in three phases. First as Sara, who can only be killed by killing her adds near her. Then by killing the brain and tentacles. He’ll spawn portals, which one player (per portal) must enter, usually melee DPS. At phase 3 it’s just a race to kill Yoggy.
Special Features:
Lots. There’s the vehicle section, the mount, hardmodes, and lots of optional stuff. If you leave up the watchers, the Yogg-Saron fight is much, much harder but in 25 man he may drop the legendary hammer Val’anyr (which you also must forge during a fight with Yogg-Saron). Additionally, there’s a completely optional hardmode fight after Yogg-Saron, a particularly difficult encounter with Alganon the Observer.
Recommended for Levels: 80-85
A lot of people love Ulduar, and there’s a lot here to love. There is an encounter for just about every type of player in the game, the environments are all pretty fun and good looking, and there’s just a lot going on here.
It’s still a popular instance that is a bit easier, but still provides a challenge for groups looking to get in on some achievements, mount, legendary, and whatnot. So yeah, I think you should do this instance if you can get a group together for it.