Delve

For the league, see Delve league.

The subterranean chart of the Azurite Mine

A delve is the exploration of the infinite Azurite Mine dungeon, released in the Delve league. The character guides a Crawler (mine cart) powered by Voltaxic Sulphite through the mines to a checkpoint. Players can start delving from act 4 onwards, when they start encountering Niko, Master of the Depths.

Mechanics

Sulphite

Voltaxic Sulphite is used to travel to undiscovered checkpoints in the Azurite Mine. From act 4 onwards, zones can spawn 3 caches of Sulphite. Clicking on it will summon Niko to harvest it. The higher the zone level, the more Sulphite is gained. In maps, the amount of Sulphite received can be increased with map quantity. Nearby party members will also receive the harvested Sulphite. The Sulphite in maps can be increased with certain Scarabs.

Players can only hold up to a certain amount of Sulphite at a time. The maximum Sulphite capacity can be upgraded using Azurite. The amount of Sulphite needed to navigate from one checkpoint to another depends on the depth and the length of the path, up to a maximum of 1100 Sulphite per segment.

Sulphite scaling based on area level

Those are base values and can be further modified by map quantity. In maps, effective area level is used instead of base area level.

Sulphite Scaling ▾ [Expand] ▾

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Darkness

Light and darkness play an important role, as the player character takes increasingly high damage over time when outside of any lit areas in the form of a stacking debuff. The debuff deals damage equal to 2% of the player's life and energy shield per second, gaining a stack every 0.25 seconds (maximum 5000 stacks). Stepping into a lit area clears the debuff. Allied minions and totems will not take darkness damage. Additionally, monsters within the darkness cannot be damaged.

Light is primarily emitted by the Crawler, cables that are generated in cleared paths, and Flares. Flares are consumable items that can be thrown the create a temporary lit area. Its radius, duration, and maximum capacity can be upgraded with Azurite. Stalkers, a monster found in Delves, can temporarily disable sources of light.

The player's resistance to darkness damage and light radius decreases when delving deeper in the mine. Darkness resistance and light radius can be upgraded with Azurite.

Generic light radius modifiers will not work in the Azurite Mine.

Crawler

The Crawler is used to navigate to undiscovered checkpoints, powered by Sulphite. The Crawler will automatically navigate to the chosen waypoint, providing light around it. If players move ahead of its path, it will greatly speed up to catch up to them and stops if players move too far away from it. The crawlers speed is based on the characters movement speed.

The Crawler will also pick up items dropped within a large radius around it, which it drops when the checkpoint and encounter is cleared.

Dynamite

Dynamite is used to destroy fractured walls, which are hidden in dark areas off the path. Each wall takes only one dynamite to destroy. Dynamite can also be used to deal damage to enemies.

Dynamite capacity, radius, and damage can be upgraded with Azurite.

Azurite Mine

The mine can be explored going downwards (increasing the difficulty) and laterally.

Progress is the mine is shared between all characters in a league; different leagues will have different layouts of the mine. When playing in parties, the process is tied to the owner of the mine and other party members cannot continue if the owner leaves.

In each delve, players navigate from one checkpoint to another undiscovered one. At the end of the checkpoint, there will usually be an encounter of some kind. Once the encounter is cleared, the Crawler will drop all the items it picked up and any loot containers nearby can be opened. Each checkpoint drops different rewards, indicated by its icon.

Grids can contain zone modifiers, increasing in difficulty. The lower the depth, the more likely a grid will have a zone modifier.

Instance

When loading into a delve checkpoint, the game will spawn an instance with all possible areas in a 5x5 grid around it. If players take a path that goes outside the instance's 5x5 grid or load a path that requires relocating the Crawler, a new instance is created. When moving from a checkpoint where the Crawler is to a nearby checkpoint, the Crawler will move there without loading a new instance. Players dying in the instance will not be able to return to it.

When in a group, a portal to the instance will spawn when the party leader creates a delve instance. If the party leader dies inside the instance, a portal will spawn.

To return to the current instance from the Mine Encampment, click the icon in the top left corner of the Subterranean Chart marked "Visit: The Mine" to teleport to the last checkpoint used.

Hidden loot

Fossil Remains in darkness

The mines contain many small containers of loot, often hidden away in the darkness. These containers do not display its item name unless players are close enough to it and have a faint sparkle around it. They are often found in side paths where the Crawler passes by.

They can contain items, fossils, resonators, flares, dynamites, or Azurite.

Fractured walls

Fractured Wall

Fractured Wall Mini-map Icon with Hidden Room

Fractured walls can be found hidden in dark areas. They will be marked on the minimap if you are close enough and and hovering over it will show the wall's health bar. These walls can be destroyed with a dynamite. Behind fractured walls are rare loot containers and sometimes, a hidden path to an inaccessible checkpoint.

There will always be at least one fractured wall in grids that do not contain checkpoints.

Hidden path

Some checkpoints have no paths leading into it. This means it is hidden behind a fractured wall. Once the wall is destroyed, players can send the Crawler to that checkpoint.

To find the hidden wall more easily, note the path creation rule:

• A checkpoint will generally only have 1, 3, or 4 paths leading out of it. 2-way nodes are rare, but are possible when the generator tries to create a path that is too long.
• A fractured wall spawns in an empty square, so nodes directly next to a hidden node are not valid options.
• It's not possible to create more than one path in a cardinal direction.
• It's not possible to overlap an existing path.

If a checkpoint has 2 paths, it is likely that there is a hidden path near it. If there are no checkpoints with 2 paths, check the checkpoints with 3 paths. It is also possible for a checkpoint with a single path (which is usually a dead-end) to contain 2 hidden paths out of it. Rarely, an overly long path to a hidden node can be generated and result in a dead end node having a single hidden wall and creating a 2-way node.

Betrayal Changes

• It is possible for a checkpoint to have only 2 paths, if 1 path connects 2 checkpoints further than 5 tiles apart.

Mineshaft

As a character levels up, Niko will dig a mineshaft that goes straight down from the Mine Encampment. Mineshaft length is shared among all characters in the league, and is based on the highest level character of that league. Niko will stop digging mineshafts at depth 34 (monster level 68).

The mineshaft is intended as a catch-up mechanic for players that don't progress delves during the campaign. The mineshaft is a straight downward path with nothing inside. It will override any node it spawns over.

Biomes

The Azurite Mine contains six common biomes, each with different monsters, encounters, and common fossil drops. Rarely, a city biome will spawn, which contains better loot and rarely, a special boss, but are more difficult and denser.

Image	Biome	Map Icon	Fossils by Rarity	Minimum Depth
				Depth	Weight
	Mines		Metallic FossilMetallic FossilStack Size: 20More Lightning modifiers No Physical modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Serrated FossilSerrated FossilStack Size: 20More Attack modifiers Fewer Caster modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Pristine FossilPristine FossilStack Size: 20More Life modifiers No Defence modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Aetheric FossilAetheric FossilStack Size: 20More Caster modifiers Fewer Attack modifiersPlace in a Resonator to influence item crafting. Shift click to unstack.	0	100
				40	100
				65	0
	Fungal Caverns		Dense FossilDense FossilStack Size: 20More Defence modifiers No Life ModifiersPlace in a Resonator to influence item crafting. Shift click to unstack., , Perfect FossilPerfect FossilStack Size: 20Improved QualityPlace in a Resonator to influence item crafting. Shift click to unstack., Corroded FossilCorroded FossilStack Size: 20More Physical Ailment or Chaos Ailment modifiers No Elemental modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Gilded FossilGilded FossilStack Size: 10Item is overvalued by vendorsPlace in a Resonator to influence item crafting. Shift click to unstack.	4	0
				20	100
	Petrified Forest		Bound FossilBound FossilStack Size: 20More Minion, Aura or Curse modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Jagged FossilJagged FossilStack Size: 20More Physical modifiers No Chaos modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Corroded FossilCorroded FossilStack Size: 20More Physical Ailment or Chaos Ailment modifiers No Elemental modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Sanctified FossilSanctified FossilStack Size: 10Numeric modifier values are lucky High Level modifiers are more commonPlace in a Resonator to influence item crafting. Shift click to unstack.	4	0
				20	100
	Abyssal Depths		, Bound FossilBound FossilStack Size: 20More Minion, Aura or Curse modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Gilded FossilGilded FossilStack Size: 10Item is overvalued by vendorsPlace in a Resonator to influence item crafting. Shift click to unstack., Lucent FossilLucent FossilStack Size: 20More Mana modifiers No Speed modifiersPlace in a Resonator to influence item crafting. Shift click to unstack.	10	0
				25	100
	Frozen Hollow		, Serrated FossilSerrated FossilStack Size: 20More Attack modifiers Fewer Caster modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Prismatic FossilPrismatic FossilStack Size: 20More Elemental modifiers No Physical Ailment or Chaos Ailment modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Sanctified FossilSanctified FossilStack Size: 10Numeric modifier values are lucky High Level modifiers are more commonPlace in a Resonator to influence item crafting. Shift click to unstack.	200	0
				40	100
	Magma Fissure		, Prismatic FossilPrismatic FossilStack Size: 20More Elemental modifiers No Physical Ailment or Chaos Ailment modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Pristine FossilPristine FossilStack Size: 20More Life modifiers No Defence modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Enchanted FossilEnchanted FossilStack Size: 20Has a Labyrinth EnchantmentPlace in a Resonator to influence item crafting. Shift click to unstack., Encrusted FossilEncrusted FossilStack Size: 10More sockets Can have white socketsPlace in a Resonator to influence item crafting. Shift click to unstack.	30	0
				50	100
	Sulphur Vents		Metallic FossilMetallic FossilStack Size: 20More Lightning modifiers No Physical modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Perfect FossilPerfect FossilStack Size: 20Improved QualityPlace in a Resonator to influence item crafting. Shift click to unstack., Aetheric FossilAetheric FossilStack Size: 20More Caster modifiers Fewer Attack modifiersPlace in a Resonator to influence item crafting. Shift click to unstack., Encrusted FossilEncrusted FossilStack Size: 10More sockets Can have white socketsPlace in a Resonator to influence item crafting. Shift click to unstack.	55	0
				75	100
	Vaal Outpost		Unknown	22	0
				83	12
				600	18
	Abyssal City		Unknown	82	0
				83	4
				220	12
				600	18
	Primeval Ruins		Unknown	210	0
				220	4
				600	12

Weights

Current theory^{[citation needed]} on weights:

The weight is scaled between the lower and upper entries based on current delve depth. See the table below for data mined values.

Example ▾ [Expand] ▾

Depth	Weight
50	0
100	100

If your character is below or at depth 50, the biome will not spawn.

If your character is between 50 and 100, the biome will spawn and the weight will increase accordingly;

Depth 51, 2 weight

Depth 52, 4 weight

...

Depth 99, 98 weight

Depth 100, 100 weight

If your character is below depth 100, the biome will always have a weight of 100

Bosses

A city biome may contain a special boss. Each boss can only spawn below a certain minimum depth.

Boss	Biome	Depth
Ahuatotli, the Blind	Vaal Outpost	35
Kurgal, the Blackblooded	Abyssal City	110
Aul, the Crystal King	Primeval Ruins	171

Minor bosses

There are other minor unique bosses for other Delve nodes, such as:

Boss	Node	Biome
Amplifier Defender	Abandoned Amplifier	Mines
Captain Stuart "Stab-First" Grenn	Frigid Recess	Frozen Hollow
Miner's Grip Awoken Giant	Haunted Tomb	Fungal Caverns
Priest of the Blood Covenant	Stonewood Hollow	Petrified Forest
6 rogue exile	Smuggler's Stash	any biome
Magmatic Golem	Restless Rubble in Magma Fissure	Magma Fissure
golem	Restless Rubble	any other biome
Primordial Beast	Beast Burrow
Lion of the Tunnels or Gorgol Terror or Blackhowl, Prime Stalker	Azurite Fissure
Diabolic Whisperer	Necromancer's Excavation

Nodes

Biome Specific Nodes:

Icon	Node name	Description	Biome
	Haunted Tomb	Contains	Fungal Caverns only
	Stonewood Hollow	Contains	Petrified Forest only
	Crystal Spire	Contains Hollow FossilHollow FossilStack Size: 10Has an Abyssal socketPlace in a Resonator to influence item crafting. Shift click to unstack.	Abyssal Depths only
	Time-Lost Cavern	Contains Glyphic FossilGlyphic FossilStack Size: 10Has a Corrupt Essence modifierPlace in a Resonator to influence item crafting. Shift click to unstack.	Frozen Hollow only
	Molten Cavity	Contains Faceted FossilFaceted FossilStack Size: 10More Gem modifiersPlace in a Resonator to influence item crafting. Shift click to unstack.	Magma Fissure only
	Humid Fissure	Contains Fractured FossilFractured FossilStack Size: 10Creates a split copy. Cannot be used to split Influenced, Enchanted, Fractured, or Synthesised items.Place in a Resonator to influence item crafting. Shift click to unstack.	Sulphur Vents only
	Mutewind Retreat Mutewind Base	Contains a Mutewind Warband. Contains Cold Items	Frozen Hollow only
	Ruined Chamber	Contents Unknown Contains Vaal Ruined Chamber which has multiple loot containers and crafting bench recipe	Vaal Outpost only
	The Grand Architect's Temple	Contains Ahuatotli, the Blind.	Vaal Outpost only
	Abyssal Chamber	Contents unknown.	Abyssal City only
	The Lich's Tomb	Contains Kurgal, the Blackblooded.	Abyssal City only
	Primeval Chamber	Contents unknown.	Primeval Ruins only
	The Crystal King's Throne	Contains Aul, the Crystal King.	Primeval Ruins only

Common Nodes:

Icon	Node name	Description
	Azurite Cavity	Contains Azurite Contains a small amount of Azurite.
	Azurite Vault	Contains Azurite Contains a medium amount of Azurite.
	Azurite Fissure	Contains Azurite Contains a large amount of Azurite.
	Variable	Contains assorted items.
	Variable	Contains weapon items.
	Variable	Contains armour items.
	Variable	Contains jewellery items.
	Variable	Contains currency items.
	Variable	Contains skill gems.
	Variable	Contains strongboxes.
	Variable	Contains maps.
	Runed Cavern	Contains a Harbinger
	Whispering Gallery	Contains a Breach
	Pulsating Grotto	Contains Monsters from Beyond
	Echoing Lair	Contains Animalistic items
	Buried Monolith	Contains a Legion encounter
	Variable	Contains mana or curse items.
	Variable	Contains minion and aura items.
	Ritual Grounds	Contains Talismans.
	Variable	Contains essences.
	Variable	Contains chaos items.
	Variable	Contains Cold items.
	Variable	Contains Lightning items.
	Variable	Contains Fire items.
	Variable	Contains Physical Items
	Prospero's Deposit	Contains Perandus items.
	Smuggler's Stash	Contains Fossils
	Redblade Retreat Redblade Base	Contains a Redblade Warband.
	Brinerot Retreat Brinerot Base	Contains a Brinerot Warband.
	Renegade Base	Contains a Renegades Warband. Contains Chaos Items

Depth Scaling ▾ [Expand] ▾

Sulphite cost caps at 1100 at depth 890 and beyond.

There is additional scaling starting at depth 1600, which caps out at around depth 2586.

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Spending Azurite

Azurite can be spent with Niko to purchase resonators. It can also be spent at the Generator to purchase flares and dynamite or upgrade their effectiveness or capacity. You can also upgrade delve attributes, such as Sulphite Capacity, Darkness Resistance, and Light Radius. The costs for these upgrades scale upwards quickly as shown in the tables below, however early upgrades can become discounted from the listed values if you delve deeper.

Sulphite Capacity ▾ [Expand] ▾

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Darkness Resistance ▾ [Expand] ▾

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Light Radius ▾ [Expand] ▾

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Flare Capacity ▾ [Expand] ▾

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Flare Radius ▾ [Expand] ▾

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Flare Duration ▾ [Expand] ▾

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Dynamite Capacity ▾ [Expand] ▾

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Dynamite Damage ▾ [Expand] ▾

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Dynamite Radius ▾ [Expand] ▾

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Version history

Version	Changes
3.13.0	Maps dropped by special sources such as deterministic chests or league rewards like those found in the Azurite Mine or the Temple of Atzoatl now use your own Atlas to determine which maps to drop, and can therefore drop maps that have been raised above their base tier due to the presence of Watchstones. Maps dropped from these sources now also take into account your Favourite Map selections. If a source such as this cannot find a compatible map from your Atlas to drop (for example, due to too few maps being completed and too few watchstones being socketed for a Tier 16 map on your Atlas to drop), it will drop a random map of the correct tier instead.
3.12.4d	The Azurite Mine is now capped at Depth Level 65,535.
3.8.0	Your Voltaxic Sulphite is now shared across all characters on the same account and in the same league. There is still a hard upper limit of 65000 Sulphite. Characters that are merged to Standard at the end of a league will bring their Sulphite with them, up to whatever your highest maximum Sulphite limit is. The tunnel Niko digs for you based on your character level is now also shared league-wide across all your characters, meaning your highest-level character will determine the depth of Niko's tunnel for all characters. This tunnel will only ever, at most, be 6 levels behind your highest-level character until you reach level 68. Previously, it was 15 levels behind by the time you reach level 68. The rate of level growth for monsters within the Azurite Mine is now faster, requiring significantly fewer depths to hit the maximum monster levels within the Mine. This was because most players progressed through the Atlas faster than the Mine, and the two difficulty levels would quickly become out of sync. As a result of the change to the depth-to-level ratio, the cost of Delves in those interim levels has been increased, but tapers back to the original costs as you get deeper. You can now find Legion encounters and rewards in the Azurite Mine.
3.4.0	Introduced to the game in the Delve leagues.