Horadric Strongrooms are special challenge rooms found inside Nightmare Dungeons in Season 9: Sins of the Horadrim. These micro-dungeons are short, fast-paced, and dense with enemies. They have their own unique mechanics.
Strongrooms are optional, but if your goal is loot and Horadric Jewels crafting, they are absolutely worth your time.
How to Find a Horadric Strongroom
Strongrooms do not appear in every Nightmare Dungeon, but there are ways to increase your chances:
- Play on higher World Tiers. Playing in Torment will increase your chances of finding a Strongroom.
- Upgrade your Wayfinder through the seasonal questline to help you locate Strongrooms within Nightmare Dungeons.
- Use Nightmare Sigils that include an affix guaranteeing a Strongroom in the dungeon.
- Inside a dungeon, watch for a flash of light and distinct sound. That is your clue that a Strongroom gateway is nearby.
Once you find it, defeat the initial ambush of monsters to open the portal and enter the Strongroom.
Inside the Strongroom
Once you are inside, the challenge begins. You will be racing against the clock to earn Horadric Attunement, a score that scales your final reward.
1. Activate Horadric Pillars
You will be given a choice to pick up to 3 Horadric Pillars. You can activate more pillars if you play at a higher difficulty level.
Pillars can either offer bonuses or be corrupted by Astaroth‘s influence, adding risk in exchange for much greater rewards. Choosing the right Pillars can change your entire Strongroom experience: stack buffs, summon tougher enemies, or both.
2. Slay Monsters to Earn Attunement
Each kill gives Attunement. You can see your Attunement score up right, next to the minimap. Completing a Pillar Ritual activates a 10-second buff where all monster kills give +2 bonus Attunement. Use that window to go on a killing spree.
3. Use Sacrifice Shrines
These unique Shrines spawn portals for enemy ambushes at your location. Risky, but use them after clearing Pillar Rituals to trigger the effects faster and gain more attunement.
Strongroom Boss and Rewards
Once time runs out or all Pillars are completed, a boss will spawn. Defeat the boss to complete the Strongroom.
After the fight, open the Grand Horadric Cache. The better your Attunement score, the better the loot.
Horadric Jewels
Strongrooms reward you with Horadric Phials and Horadric Tomes.
Tomes allow you to raft Horadric Jewels at Wayfinders, using Horadric Phials and Gem Fragments as materials. These powerful gems socket into Amulets and both Ring slots, and play a big role in boosting your Horadric Spell.
Horadric Jewels always include a +120 Armor and +6% Resistance to All Elements in addition to their power. This allows all players to not sacrifice armor and resistance in favor of power.
Here is the list of Horadric Jewels:
| Horadric Jewel | Effect |
|---|---|
 Seal of Control | While you have two or more Arcana from the School of Control equipped, gain 45%[+] Control Duration and 30%[+] Lucky Hit Chance. |
| Seal of Power | While you have two or more Arcana from the School of Power equipped, gain 25%[+] Movement Speed and 15%[+] Critical Strike Chance. |
| Seal of Denial | While you have two or more Arcana from the School of Denial equipped, gain 30%[x] more Barrier, Fortify and Thorns. |
 Horadric Crest | For each Arcana from a unique School you have equipped, gain 5%[+] Damage Reduction and 1%[+] Maximum Resistance to All Elements. |
 Reverie Horn | After you injure or kill an enemy, your Summons are empowered, growing larger and dealing 30%[x] more damage for 4 seconds. |
| Scornful Light | You deal 20%[x] and take 10%[x] more Elemental damage. |
| Tyrant Bane | After you deal damage over time to an enemy, they take 0.33%[x] more damage over time from you forever. |
| Liminal Echo | If you would take fatal damage, instead prevent that damage, invoke Propulsion, and become Invulnerable for 3 seconds. This can only occur once every 75 seconds. |
| Idol From Below | You gain 6%[x] primary stat, 8%[x] maximum life and you are always Unhindered. However, you will be hunted in Sanctuary’s darkest places by Jewel Guardians who were entombed to protect this relic. |
 Myriad Stone | After you cast your Catalytic Skill, if it is an Ultimate, gain 30%[+] Attack Speed for 10 seconds. |
| Spark of Creation | After you cast your Catalytic Skill, gain 10 Primary Resource. |
| Luminate Eye | Your Catalytic Skill gains 25%[+] Cooldown Reduction. |
 Brilliant Sigil | Your Infusions are 150%[x] more potent. |
 Elemental Brand | Your Catalytic Skill deals 33% damage of your Infusion’s element over 3 seconds. Lucky Hit: Dealing damage of your Infusion’s element has up to a 33% chance to trigger its secondary effect. |
 The Starflux | Your Catalysts deal 100%[x] more damage. However, you lose control over Horadric Spellcraft, causing your Catalysts to inherit Infusions randomly. |
Refer to your chosen build guide to see which Horadric Jewel fits best. Not sure what to play this season? Our Diablo 4 Tier Lists can help you decide.
