Diablo 4 Season 9: The Ultimate Strongroom Farming Guide

Diablo 4 Season 9 introduces a powerful new farming mechanic-Horadric Strongrooms has quickly become one of Diablo 4 Items the most efficient and rewarding activities for seasonal progression, gear upgrades, and crafting material acquisition. These special, timed challenge rooms appear in Nightmare Dungeons and Escalating Nightmares and offer significantly increased loot potential if you know how to farm them correctly.

This comprehensive guide covers how Strongrooms work, how to access and optimize them, what builds perform best, and strategies to maximize rewards while minimizing risk.

What Are Horadric Strongrooms?

Horadric Strongrooms are elite-filled dungeon chambers introduced in Season 9, found inside Nightmare Dungeons and Escalating Nightmares. These are timed mini-challenges that push players into fast-paced fights under increasing pressure. They're not guaranteed in every dungeon unless specific conditions are met, and they operate on unique mechanics that make them extremely rewarding-but also deadly.

Here's what makes Strongrooms different:

Time-limited: Once activated, players must quickly defeat waves of elite enemies to build "attunement" before time runs out.
High Density: These rooms spawn large packs of monsters, many of which are elite or have affix-enhanced abilities.
Reward Scaling: The longer you stay and the more you engage with the mechanics (especially Attunement Pillars), the better your loot becomes.
Boss Mechanic: When the attunement bar is full, a powerful final boss spawns. Defeating it grants the highest-tier rewards.

How to Access Strongrooms

To access a Strongroom, you need to meet specific conditions within a Nightmare Dungeon run:

Requirements:

A Nightmare Dungeon Sigil (Tier 1+).
A Horadric Strongroom affix on the sigil for a guaranteed spawn.
Ideally, Sigils that spawn Escalating Nightmares, which offer higher reward multipliers and additional boss challenges.

Where to 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 buy D4 materials a Strongroom, look for its marked door or portal. Once you activate it, the countdown begins.