Where to Diablo 4 Items find the Strongroom affix:

You can re-roll sigil affixes using the Occultist to try and get the "Horadric Strongroom" affix.
Crafting Nightmare Sigils via the Occultist can also randomly yield this affix.

Once inside a dungeon with a Strongroom, look for its marked door or portal. Once you activate it, the countdown begins.

What Rewards Do Strongrooms Give?

The loot from Strongrooms is highly desirable and includes materials and Diablo 4 Items essential to endgame and mastercrafting. Depending on how many Attunement Pillars you interact with and how long you survive, your loot gets better.

Guaranteed & Random Rewards:

2,000-3,000+ Obducites per run (used for Greater Affix crafting)
Forgotten Souls (used to reroll item stats or upgrade Legendaries)
Legendary Items, often with Greater Affixes
High-tier Rare gear with optimal stat distribution
Seasonal Reputation progression points
Boss-specific loot if you complete the final boss phase

If you stack enough Attunement and successfully slay the room's boss, you can sometimes walk away with multiple legendaries, powerful crafting mats, and build-defining upgrades.

Understanding the Attunement System

Inside a Strongroom, you'll interact with Attunement Pillars that spawn waves of enemies. Each pillar activated adds to your Attunement Bar, which tracks your progress. Once it fills, the final boss (often Asteroth in Escalated Strongrooms) appears.

Some pillars will offer tradeoffs like:

+25% Attunement but no dodge allowed
+20% Attunement but no health potions
+15% Attunement, but enemies are shadow-enhanced

These modifiers can make the Strongroom brutally difficult, but the increased attunement will rapidly boost your progress toward the final boss and better rewards.

Key Rule:

You do NOT need to buy duriel mats fight the boss to keep your loot. If you're feeling underpowered, simply leave once you're satisfied with what you've earned.