Season 9 of Diablo 4, titled Sins of the Horadrim, introduces a fresh activity for players: Horadric Strongrooms. These are short, combat-focused areas packed with enemies, rewards, and mechanics tied to the season’s new systems. If you’ve played past seasons, you can think of them as Season 9’s version of Rootholds or Hellbreaches — but with a unique twist. Even better, they give players a free taste of Vessel of Hatred-style gameplay without needing to buy the expansion.
How to Unlock Horadric Strongrooms
To begin accessing Strongrooms, players need to progress through the seasonal storyline. As part of that journey, you’ll receive a special tool called the Wayfinder. This item marks Horadric Strongrooms that are hidden inside Nightmare Dungeons. Since Nightmare Dungeons are already popular for leveling and loot grinding, you’ll likely run into Strongrooms while naturally progressing through your seasonal grind.
How Strongrooms Work
When you enter a Horadric Strongroom, you’ll start off by activating a ritual pillar. This summons several waves of enemies. Once the area is cleared, you’ll pick one of several modifiers — each changes how the next phase of the Strongroom plays out. Some increase your power, others raise the difficulty but promise better loot.
The main objective is straightforward:
- Fight through waves of enemies
- Build up a meter called attunement
- Defeat the final boss before time runs out
The more attunement you gather, the better your end rewards will be. Throughout the run, you may find Sacrifice Shrines — interacting with these gives temporary boosts to help you build attunement faster and more efficiently.
Rewards from Strongrooms often include:
- Arcana – used to craft seasonal Horadric Spells
- Escalation Sigils – unlocks new Escalating Nightmare Dungeon content
Comparison to the Kurast Undercity
Players who own the Vessel of Hatred DLC might notice that Strongrooms share some similarities with the Kurast Undercity, one of the expansion’s main endgame dungeons. Both involve collecting attunement and working against the clock — but they play quite differently in practice. Here’s what sets them apart:
- Length & Complexity: Strongrooms are short and simple. The Kurast Undercity, on the other hand, spans multiple levels and requires more time and planning.
- Timer Pressure: In Strongrooms, you can’t fail. In the Undercity, if you don’t finish in time, you lose your progress and rewards.
- Extra Mechanics: The Undercity includes Afflicted enemies (which extend your timer when killed), Spirit Beacons (which guide your path), and Tribute/Bargain options that influence your loot.
- Failure Risk: Strongrooms are beginner-friendly. The Undercity punishes mistakes with total reward loss.
So while they share core concepts, the Kurast Undercity is the high-stakes version, whereas Strongrooms offer a safer, more casual take.
Even if you’re not planning to buy the expansion, Strongrooms are a great way to preview what Vessel of Hatred offers. They’re fast, fun, and tied directly into the core seasonal progression. Whether you’re chasing Arcana for crafting, farming Escalation Sigils, or just want something new to do, Strongrooms are well worth your time.
