Season 9 brings new content to Diablo 4 and an old friend returns. You have already fought against him in the campaign – and this time he remains permanently in the ARPG.
With Season 9, Blizzard shakes up the endgame in Diablo 4 and revamps existing activities. Horadric vaults appear in Nightmare Dungeons, containing powerful enemies and strong loot. In the “Escalating Nightmares,” you will be sent through three consecutive Nightmare Dungeons, where the difficulty increases, but so do the rewards.
Who is returning in Diablo 4? Besides new content, a fan favorite is also returning: Astaroth. The wicked demon belongs to Mephisto’s lieutenants and originally encountered you at the end of Act 2 in the campaign. Astaroth rides on his Amalgam of Wrath, with rider and mount sharing the health bar and fighting as one unit.
With his return, there is a novel strategy in the boss fight, as Astaroth splits into two independent bosses with unique combos.
In “Escalating Nightmares,” you will meet Astaroth
When can I fight Astaroth? Season 9 is expected to start on July 1, 2025. Then you can dive into the new endgame content, including the encounter with Astaroth. However, he is not part of the Hideout bosses. Instead, he awaits you at the end of the Escalating Nightmares – provided you master all three dungeons.
To even enter the new activity, you need so-called Ascension seals. These drop starting from torment level 1 in the horadric chests found in the vaults. With an active seal, you can start in the first of three consecutive Nightmare Dungeons.
If you successfully complete the third Nightmare Dungeon in the series, you will reach Astaroth’s hideout and can take revenge on the campaign boss.
What the community says about the return: Astaroth is one of the popular bosses in the campaign of Diablo 4. In a Reddit thread from June 2023, a user writes: “Dear Blizzard, can we please fight Astaroth again?” The thread gathered over 3,800 upvotes.
Two years later, it’s finally time, and you can actually fight Astaroth outside the campaign. In a recent Reddit post from May 22, 2025, LoatheBurger writes that he thinks it’s “pretty cool” that the boss apparently dismounts during the fight.
In the comments, MostPutridSmell agrees: “I feel the same – his design is just really cool.” And SheWhoHates hopes for a suitable mount drop in the style of his “Amalgam of Wrath.”
The innovations around the Nightmare Dungeons are expected to remain beyond Season 9. From then on, you can additionally activate new Nightmare seals directly within the dungeons without having to leave the dungeon each time.
For those who want to test the changes now: The PTR (test server) for Season 9 runs until June 3. There you can not only pay Astaroth a visit, but also examine all the new features. More information, including German patch notes, can be found here: Blizzard shakes up the endgame of Diablo 4 with Season 9, and you can play it today
