Sepulcher of the first ones
The Sepulcher of the First Ones is a First Ones-style structure overlooking Zereth Mortis from a secluded island on the eastern end of the zone. Initially, you will need to use an Ancient Translocator located east of Pilgrim's Grace to get to the raid which is unlocked at the end of Chapter 4 of the Patch 9.2 questline, Forging a New Path.
The raid entrance is located on a floating isle in Zereth Mortis. First, you must fly to Pilgrim's Grace. Upon arriving there, climb up a set of stairs to your left, interact with the Ancient Translocator to fly to the Sepulcher raid.
After flying is unlocked in Zereth Mortis, you can simply fly to the raid entrance.
Ilevel requirements follow similar trends to previous raids of the expansion, where the majority of the bosses have a specific set ilevel for loot they drop, with the final three being higher (and thus, will no doubt require a higher ilevel to defeat).
LFR will drop Item Level 239 gear for the majority of the bosses, rising to 246 for the last three, with a 220+ ilevel entry requirement.
Normal will drop Item Level 252 gear for the majority of the bosses, rising to 259 for the last three, with a 239+ ilevel entry requirement.
Heroic will drop Item Level 265 gear for the majority of the bosses, rising to 272 for the last three, with a 252+ ilevel entry requirement.
Mythic will drop Item Level 278 gear for the majority of the bosses, rising to 285 for the last three, with a 265+ ilevel entry requirement.
Sepulcher of the First Ones Boss Order
Sepulcher has a semi-linear boss order, with a few points where you need to defeat all available bosses before being allowed to continue.
Vigilant Guardian is the first boss of the instance.
Defeating Vigilant Guardian unlocks Dausegne, Skolex and Artificer Xy'mox.
The raid can take a couple different directions now, depending on which bosses they want to kill.
Defeating Dausegne unlocks the Prototype Pantheon, which then unlocks Lihuvim when defeated.
Defeating both Skolex and Artificer Xy'mox unlocks Halondrus.
When both Lihuvim and Halondrus are defeated, Anduin Wrynn is unlocked.
Defeating Anduin Wrynn unlocks both Lords of Dread and Rygelon.
When both Lords of Dread and Rygelon are defeated, The Jailer is unlocked.
Tier Set Armor Pieces
Tier Set armor pieces drop as tokens from bosses in the new raid in Eternity's End. Below, you will find a list of bosses that drop specific tier set tokens.
Lihuvim, Principal Architect, the sixth boss, drops Gloves.
Halondrus the Reclaimer, the seventh boss, drops Legs.
Anduin Wrynn, the eighth boss, drops Helm.
Lords of Dread, the ninth boss, drops Shoulders.
Rygelon, the tenth boss, drops Chest.
The Raid
The Jailer has breached the Sepulcher, the mysterious heart of the Shadowlands. Should he control its primordial power, he will reshape the cosmos with Death at the fore. As Zovaal prepares to dominate reality, champions of Azeroth charge forth to stop him. Will their resolve outmatch his?
Vigilant Guardian
This eternal guardian lies in wait, keeping a timeless vigil over the entrance to the Sepulcher of the First Ones.Skolex, the Insatiable Hunger
With the Sepulcher of the First Ones vulnerable, devourers swarm in to feed their hunger. Among these aberrations is the ravenous Skolex. As the great worm consumes vast amounts of ephemera, the Sepulcher is thrown out of balance and threatens to collapse upon itself.Artificer Xy'Mox
After his defeat in Castle Nathria, Artificer Xy'mox sank back into the shadows to plot his next heist. With the Sepulcher of the First Ones now vulnerable, Xy'mox has summoned the full might of the Xy Cartel to plunder the ancient knowledge and powerful relics buried there.Dausegne, The Fallen Oracle
Dominated by the Jailer, Dausegne leads the Mawsworn in a battle to gain control of the Forge of Afterlives. The Jailer plans to use its power to unleash an eternity of torment upon all of reality.Prototype Pantheon
Bereft of the cosmic spirits of the Eternal Ones, these incomplete host bodies can only carry out their base directives without mercy or compassion. With the enemy at the gates, Lihuvim has little choice but to activate these dangerous prototypes.Lihuvim, Principal Architect
With meticulous care, Lihuvim weaves ephemera into being in accordance with the hallowed will of the First Ones. Now this process is threatened as Mawsworn forces seek to claim this power.Halondrus the Reclaimer
For eons Halondrus traversed the cliffs of the Sepulcher of the First Ones, fulfilling its sacred purpose of reclaiming ephemera and returning it to the great cycle. With intruders now throwing this pattern into anarchy, the ancient keeper will do whatever it must to maintain order.Anduin Wrynn
Controlled by Domination magic, Anduin is being forced to aid the Jailer's plan to remake reality. As time runs out to stop him, the champions of Azeroth must make a difficult choice: defeat the young king to save the cosmos, or risk everything in order to restore his soul.Lords of Dread
Using subterfuge and guile, the nathrezim have worked for eons to bring the Jailer's plan to fruition. Now, on the brink of their master's victory, they only need to complete one final task to ensure none are left to resist the new order of the cosmos.Rygelon
Drawn to observe the fateful events unfolding within the Sepulcher of the First Ones, Rygelon succumbed to the Jailer's domination. Now this constellar turns its cosmic power against any who would oppose the Banished One.The Jailer
For untold millennia, the Jailer patiently unfolded his plan to reach the heart of the Sepulcher. Now poised upon the precipice of his final victory, the heroes of Azeroth must rally to prevent the Jailer from dominating all of reality.