How to unlock Nightmare Dungeons in Diablo 4 and how they work

If you want to know more about Diablo 4 Nightmare Dungeons, you've come to the right place. They put a spin on regular dungeons by increasing their difficulty and they also allow you to upgrade Glyphs, so they're handy for squeezing out that extra bit of power from your build. You'll need Nightmare Sigils to access them, which can drop randomly on the Nightmare World Tier, so don't worry if you don't get one right away. With that in mind, here's where to find Nightmare Sigils and how the Nightmare Dungeons that they unlock work.

Where to get Nightmare Sigils

To get hold of a Nightmare Sigil, first, you'll need to finish the campaign and unlock the Nightmare World Tier, which should happen by the time you reach level 50. When you change your world tier to Nightmare, Sigils will have a chance to drop from Tree of Whispers caches, world bosses, Helltides, and dungeons, but depending on your luck, it might be a while before you see one. 

It's easy to spot a Nightmare Sigil when it does drop as it is bright blue, but you'll need to pick these items up manually rather than running over them as you do with gold. They are stored under the Consumables tab in your inventory, and you'll notice they have different tier levels associated with them. This is directly tied to the difficulty of the Nightmare Dungeon it unlocks.

You can also craft Nightmare Sigils at the Occultist, but you need to complete at least one Nightmare Dungeon to unlock this ability and its priority quest. The good news is that once you gain access to these dungeons, you'll be swimming in Nightmare Sigils before the end of your first run. That means you'll have plenty to salvage for materials to craft more.

What are Nightmare Dungeons in Diablo 4?

Nightmare Dungeons are Diablo 4's take on Mythic+ dungeons (if you play WoW) or Greater Rifts (if you played Diablo 3). They take the existing dungeons, increase the difficulty, and add random affixes to them, which are basically random buffs to both yourself and enemies or added environmental hazards you might need to avoid. Unlike Mythic+ and Greater Rifts, though, Nightmare Dungeons aren't timed, and you'll get to upgrade one of your Glyphs after successful completion.

To access a Nightmare Dungeon, you'll need a Nightmare Sigil to activate it. Sigils are tied to specific dungeons, so you have no choice which one you venture into. If you want a specific tier, you can craft a Nightmare Sigil of that level, but again, you won't have any control over which dungeon it unlocks. In practice, this means you'll be collecting entry tickets in your stash like consumables that will take you to specific Dungeons. On the plus side, at least you'll be able to salvage the ones you don't need.

To activate a Nightmare Dungeon, right-click the associated Nightmare Sigil in your inventory, and the dungeon will pulse on the map so you can find it easily. If you're in a group, others in your party will receive a pop-up message asking them to accept the dungeon activation.

At the end of the dungeon run, you'll receive two pieces of loot which are usually legendary quality, though there's a good chance one will be a Unique. You will also find an altar that lets you upgrade your Glyphs, similar to the way the Legendary Gems worked in Diablo 3. The higher the tier, the more you can upgrade.

Diablo 4 Nightmare Dungeon affixes

Here are the Nightmare Dungeon affixes I've encountered so far: 

 Positive affixes

• Frost Damage
• Poison Damage
• Shadow Damage
• Gold Find
• Increased Healing
• Reduce Cooldowns on Kill

Negative affixes 

• Empowered Elites (Cold Enchanted)
• Empowered Elites (Shock Lance)
• Monster Lightning Damage
• Monster Fire Damage
• Monster Poison Damage
• Monster Bleeding Damage
• Monster Attack Speed
• Monster Shadow Damage Over Time
• Lightning Storm
• Armor Breakers
• Drifting Shade
• Volcanic
• Stormbane's Wrath