Lightless Arbor Dungeon Guide

Lightless Arbor Dungeon Last Epoch

Lightless Arbor is a dungeon themed around darkness, with its primary function being a gold sink. It features a light-based mechanic that buffs players and debuffs enemies. The dungeon also incorporates a juicing mechanic, where spending gold increases rewards. The dungeon culminates in a boss fight with two distinct stages.

In this guide, we’ll cover the layout, boss mechanics, and the rewards you can obtain from the Lightless Arbor dungeon.

Accessing the Dungeon

To enter the Lightless Arbor dungeon, you need a Lightless Arbor Key. These keys drop randomly from enemies but can also be target farmed from Timeline Bosses and the Arena of Champions (though the Arena is not recommended due to the low drop rate).

Once you’ve obtained a Key (or multiple keys), you need to head to the Lightless Arbor in the Ruined Era. Start at the Surface waypoint and head north towards the entrance leading to The Shrouded Ridge. Upon arriving at The Shrouded Ridge, head directly north until you reach the entrance to the Lightless Arbor. Right-clicking on your Lightless Arbor Key will highlight this section of the map.

Dungeon Rewards

The Lightless Arbor dungeon offers many valuable rewards, including:

• Items acquired through the Vaults of Uncertain Fate.
• Boss-specific Uniques that can only be obtained from defeating the dungeon’s boss.
• Dungeon modifier rewards, which are influenced by modifiers attached to the doors within the dungeon.

These rewards provide powerful loot and progression opportunities, making the Lightless Arbor a highly rewarding dungeon to complete.

The Vaults of Uncertain Fate

The most notable reward in Lightless Arbor is the ability to spend gold on modifiers that increase the rewards found behind the Vaults of Uncertain Fate.

After defeating The Mountain Beneath and entering the next area, you will encounter a door that leads to the Vaults. Interacting with this door initiates a series of choices. You can choose to add a modifier to the vault for gold or skip it. Each additional choice beyond the first increases the cost of adding further modifiers, eventually reaching the point where you either hit your modifier limit or the cost of modifiers becomes too expensive to continue.

Opening the Vault

Once you're done choosing modifiers, you can open the Vault. All of the modifiers you selected will be accounted for, and the reward will be placed inside one or more chests. If enough modifiers were selected, this will result in an explosion of items, offering a massive reward that can include Exalted and even Unique items!

The more modifiers you add, the greater the potential rewards, but keep in mind that the cost of modifiers increases with each choice, so you need to balance your investment wisely.

Uniques

There are 4 different Uniques that The Mountain Beneath can drop, with different tier requirements for each:

• Peak of the Mountain drops from tier 1 and higher.
• Foot of the Mountain drops from tier 2 and higher.
• Face of the Mountain drops from tier 3 and higher.
• Core of the Mountain only drops from tier 4.

Each of these Uniques has a specific tier requirement, meaning that you will need to progress through higher tiers to access the more powerful Uniques.

Dungeon Modifier Rewards

When running a dungeon, you stack modifiers that have both positive and negative effects. There are two primary sources of modifiers:

1. Dungeon Tiers: Any tier of dungeon beyond tier 1 has a modifier attached to it. This modifier changes daily, so it can be worthwhile to save keys for a particularly good modifier that you can farm.
2. Doors: Every door you open to move to the next part of the dungeon adds a modifier. There are two doors in total—one to go from floor 1 to floor 2, and another to move from floor 2 to The Mountain Beneath.

Additionally, Lightless Arbor features an extra set of modifiers for the Vaults of Uncertain Fate. When interacting with the vaults, players choose these modifiers by paying gold to increase the rewards.

Dungeon Modifiers

There are many modifiers that players can encounter in dungeons, ranging from increased chances to find a certain type of Exalted item to increased crafting materials. These modifiers add layers of complexity and reward to the dungeon runs.

• Higher-tier Dungeons offer better versions of lower-tier modifiers as well as new modifiers. This makes progressing to higher tiers especially valuable, as you can gain more powerful rewards and advantages (See Difficulty for more information on tiers).

Modifiers can significantly affect your dungeon run, so knowing which ones to prioritize can help optimize your farming efforts and reward acquisition.

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Door Modifiers

Tier 1 Reward Modifiers

Floor 1

• No modifiers.

Floor 2

• Enemies drop slightly more Glyphs.
• Enemies drop more Rare armor.
• Enemies drop more Rare helmets.
• Enemies drop more Rare jewelry.
• Enemies drop more Rare relics.
• Enemies drop more Rare weapons.
• Enemies drop slightly more Runes.

Floor 3

• The dungeon boss drops Rare Jewelry.
• The dungeon boss drops additional Glyphs.
• The dungeon boss drops additional Rare Weapons.
• The dungeon boss drops additional Rare Items.
• The dungeon boss drops additional Runes.

Tier 2 Reward Modifiers

Floor 1

• The dungeon boss drops Exalted Jewelry.
• The dungeon boss drops additional Exalted Items.
• The dungeon boss drops additional Exalted Weapons.
• The dungeon boss drops additional Glyphs.
• The dungeon boss drops additional Idols.
• The dungeon boss drops additional Runes.
• The dungeon boss drops a Set Item.

Floor 2

• Enemies drop slightly more Exalted amulets.
• Enemies drop slightly more Exalted helmets.
• Enemies drop slightly more Exalted relics.
• Enemies drop slightly more Exalted rings.
• Enemies drop slightly more Exalted weapons.
• Enemies drop slightly more Glyphs.
• Enemies drop slightly more Runes.

Floor 3

• The dungeon boss drops Exalted Jewelry.
• The dungeon boss drops additional Exalted Items.
• The dungeon boss drops additional Exalted Weapons.
• The dungeon boss drops additional Glyphs.
• The dungeon boss drops additional Idols.
• The dungeon boss drops additional Runes.
• The dungeon boss drops a Set Item.

Tier 3 Reward Modifiers

Floor 1

• Enemies drop more Exalted amulets.
• Enemies drop more Exalted helmets.
• Enemies drop more Exalted relics.
• Enemies drop more Exalted rings.
• Enemies drop more Exalted weapons.
• Enemies drop more Glyphs.
• Enemies drop more Runes.
• The dungeon boss drops a Unique Item.
• The dungeon boss drops many Idols.

Floor 2

• Enemies drop more Exalted amulets.
• Enemies drop more Exalted helmets.
• Enemies drop more Exalted relics.
• Enemies drop more Exalted rings.
• Enemies drop more Exalted weapons.
• Enemies drop more Glyphs.
• Enemies drop more Runes.

Floor 3

• The dungeon boss drops much Exalted Jewelry.
• The dungeon boss drops many Exalted Items.
• The dungeon boss drops many Exalted Weapons.
• The dungeon boss drops many Glyphs.
• The dungeon boss drops many Idols.
• The dungeon boss drops many Runes.
• The dungeon boss drops a Unique Item.

Tier 4 Reward Modifiers

Floor 1

• Enemies drop substantially more Exalted amulets.
• Enemies drop substantially more Exalted helmets.
• Enemies drop substantially more Exalted relics.
• Enemies drop substantially more Exalted rings.
• Enemies drop substantially more Exalted weapons.
• The dungeon boss drops a Unique Weapon.
• Enemies drop substantially more Glyphs.
• Enemies drop substantially more Runes.
• The dungeon boss drops a horde of Idols.

Floor 2

• Enemies drop substantially more Exalted amulets.
• Enemies drop substantially more Exalted helmets.
• Enemies drop substantially more Exalted relics.
• Enemies drop substantially more Exalted rings.
• Enemies drop substantially more Exalted weapons.
• Enemies drop substantially more Glyphs.
• Enemies drop substantially more Runes.

Floor 3

• The dungeon boss drops a horde of Exalted Jewelry.
• The dungeon boss drops a horde of Exalted Items.
• The dungeon boss drops a horde of Exalted Weapons.
• The dungeon boss drops a Glyph of Despair.
• The dungeon boss drops a horde of Glyphs.
• The dungeon boss drops a horde of Idols.
• The dungeon boss drops a horde of Runes.
• The dungeon boss drops a Unique Weapon.
• The dungeon boss drops 2 Unique Items.

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Vault Modifiers

Vault Modifiers directly affect the rewards found in the Vaults of Uncertain Fate. Tier 1 offers lower-quality choices compared to tiers 2-4, primarily because Exalted items cannot drop in Tier 1. Due to area level, the Tier 4 dungeon is the only one that can drop Exalted items with a Tier 7 affix.

Additionally, the maximum number of modifiers that can be purchased increases with each tier level:

• Tier 1: 8 modifiers
• Tier 2: 9 modifiers
• Tier 3: 10 modifiers
• Tier 4: 11 modifiers

The higher the tier, the more modifiers you can add, enhancing the potential rewards from the Vault.

Tier 1 Reward Modifiers

• A random chest drops 25% more items (multiplicative with other modifiers)
• A random chest drops 45% more items (multiplicative with other modifiers)
• Adds a chest that drops a Magic item, a Rare item, and a Unique item.
• Adds a chest that drops a Rare helmet, Rare body armor, Rare gloves, and Rare boots.
• Adds a chest that drops many Affix Shards.
• Adds a chest that drops many Runes and Glyphs.
• Adds a chest that drops several Idols.
• Adds a chest that drops several Rare helmets.
• Adds a chest that drops several Rare items.
• Adds a chest that drops several Rare pairs of boots.
• Adds a Lightless Arbor Key to a random chest.
• Adds a Unique item to a random chest.
• Adds a Unique item to every chest.
• Adds an additional Rare pair of boots to all chests.
• Adds an additional Glyph of Chaos to all chests.
• Adds an additional Glyph of Hope to all chests.
• Adds an additional Rare item to all chests.
• Adds an additional Rune of Shattering to all chests.
• Adds an Idol to every chest.
• Adds many Glyphs to a random chest.
• Adds many Runes to a random chest.
• Adds several pieces of Rare Jewelry to a random chest.
• Adds several Rare Weapons to a random chest.
• All chests drop 15% more items (multiplicative with other modifiers).
• All chests drop 30% more items (multiplicative with other modifiers).
• All items from every chest have a 20% chance to be duplicated. This is additive with other item duplication effects. Duplication chance above 100% can result in more copies.
• All items from every chest have a 50% chance to be duplicated. This is additive with other item duplication effects. Duplication chance above 100% can result in more copies.
• Duplicates all items from a random chest. This is additive with other item duplication effects.
• Duplicates all Unique items from every chest. This is additive with other item duplication effects.
• Duplicates every chest. This occurs after modifiers that apply to a random chest have been applied.
• Triplicates every chest. This occurs after modifiers that apply to a random chest have been applied.

Tier 2 Reward Modifiers

• A random chest drops 25% more items (multiplicative with other modifiers)
• A random chest drops 45% more items (multiplicative with other modifiers)
• Adds a chest that drops a Rare item, an Exalted item, a Unique item, and a Set item.
• Adds a chest that drops a Rare weapon, an Exalted weapon, and a Unique weapon.
• Adds a chest that drops an Exalted helmet, Exalted body armor, Exalted gloves, and Exalted boots.
• Adds a chest that drops many Affix Shards.
• Adds a chest that drops many Runes and Glyphs.
• Adds a chest that drops several Exalted helmets.
• Adds a chest that drops several Exalted items.
• Adds a chest that drops several Idols.
• Adds a Lightless Arbor Key to a random chest.
• Adds a Set Item to a random chest.
• Adds a Unique Item to a random chest.
• Adds a Unique Item to every chest.
• Adds a Unique Weapon to a random chest.
• Adds additional Exalted Relic to all chests.
• Adds an additional Exalted Item to all chests.
• Adds an additional Glyph of Chaos to all chests.
• Adds an additional Glyph of Despair to all chests.
• Adds an additional Rune of Shattering to all chests.
• Adds an additional Set Item to all chests.
• Adds an Idol to every chest.
• Adds many Glyphs to a random chest.
• Adds many Runes to a random chest.
• Adds several Exalted Weapons to a random chest.
• Adds several pieces of Exalted Jewelry to a random chest.
• All chests drop 15% more items (multiplicative with other modifiers).
• All chests drop 20% more exalted items (multiplicative with other modifiers).
• All chests drop 30% more items (multiplicative with other modifiers).
• All items from every chest have a 20% chance to be duplicated. This is additive with other item duplication effects. Duplication chance above 100% can result in more copies.
• All items from every chest have a 50% chance to be duplicated. This is additive with other item duplication effects. Duplication chance above 100% can result in more copies.
• Duplicates all items from a random chest. This is additive with other item duplication effects.
• Duplicates all Unique items from every chest. This is additive with other item duplication effects.
• Duplicates every chest. This occurs after modifiers that apply to a random chest have already been applied.
• Triplicates every chest. This occurs after modifiers that apply to a random chest have already been applied.

Tier 3 Reward Modifiers

• A random chest drops 25% more items (multiplicative with other modifiers)
• A random chest drops 45% more items (multiplicative with other modifiers)
• Adds a chest that drops a Rare item, an Exalted item, a Unique item, and a Set item.
• Adds a chest that drops a Rare weapon, an Exalted weapon, and a Unique weapon.
• Adds a chest that drops an Exalted helmet, Exalted body armor, Exalted gloves, and Exalted boots.
• Adds a chest that drops many Affix Shards.
• Adds a chest that drops many Runes and Glyphs.
• Adds a chest that drops several Exalted helmets.
• Adds a chest that drops several Exalted items.
• Adds a chest that drops several Idols.
• Adds a Lightless Arbor Key to a random chest.
• Adds a Set Item to a random chest.
• Adds a Unique Item to a random chest.
• Adds a Unique Item to every chest.
• Adds a Unique Weapon to a random chest.
• Adds additional Exalted Relic to all chests.
• Adds an additional Exalted Item to all chests.
• Adds an additional Glyph of Chaos to all chests.
• Adds an additional Glyph of Despair to all chests.
• Adds an additional Rune of Ascendance to all chests.
• Adds an additional Set Item to all chests.
• Adds an Idol to every chest.
• Adds many Glyphs to a random chest.
• Adds many Runes to a random chest.
• Adds several Exalted Weapons to a random chest.
• Adds several pieces of Exalted Jewelry to a random chest.
• All chests drop 15% more items (multiplicative with other modifiers).
• All chests drop 20% more exalted items (multiplicative with other modifiers).
• All chests drop 30% more items (multiplicative with other modifiers).
• All items from every chest have a 20% chance to be duplicated. This is additive with other item duplication effects. Duplication chance above 100% can result in more copies.
• All items from every chest have a 50% chance to be duplicated. This is additive with other item duplication effects. Duplication chance above 100% can result in more copies.
• Duplicates all items from a random chest. This is additive with other item duplication effects.
• Duplicates all Unique items from every chest. This is additive with other item duplication effects.
• Duplicates every chest. This occurs after modifiers that apply to a random chest have already been applied.
• Triplicates every chest. This occurs after modifiers that apply to a random chest have already been applied.

Tier 4 Reward Modifiers

• A random chest drops 25% more items (multiplicative with other modifiers)
• A random chest drops 45% more items (multiplicative with other modifiers)
• Adds a chest that drops a Rare item, an Exalted item, a Unique item, and a Set item.
• Adds a chest that drops a Rare weapon, an Exalted weapon, and a Unique weapon.
• Adds a chest that drops an Exalted helmet, Exalted body armor, Exalted gloves, and Exalted boots.
• Adds a chest that drops many Affix Shards.
• Adds a chest that drops many Runes and Glyphs.
• Adds a chest that drops several Exalted helmets.
• Adds a chest that drops several Exalted items.
• Adds a chest that drops several Idols.
• Adds a Lightless Arbor Key to a random chest.
• Adds a Set Item to a random chest.
• Adds a Unique Item to a random chest.
• Adds a Unique Item to every chest.
• Adds a Unique Weapon to a random chest.
• Adds additional Exalted Relic to all chests.
• Adds an additional Exalted Item to all chests.
• Adds an additional Glyph of Chaos to all chests.
• Adds an additional Glyph of Despair to all chests.
• Adds an additional Rune of Ascendance to all chests.
• Adds an additional Set Item to all chests.
• Adds an Idol to every chest.
• Adds many Glyphs to a random chest.
• Adds many Runes to a random chest.
• Adds several Exalted Weapons to a random chest.
• Adds several pieces of Exalted Jewelry to a random chest.
• All chests drop 15% more items (multiplicative with other modifiers).
• All chests drop 20% more exalted items (multiplicative with other modifiers).
• All chests drop 30% more items (multiplicative with other modifiers).
• All items from every chest have a 20% chance to be duplicated. This is additive with other item duplication effects. Duplication chance above 100% can result in more copies.
• All items from every chest have a 50% chance to be duplicated. This is additive with other item duplication effects. Duplication chance above 100% can result in more copies.
• Duplicates all items from a random chest. This is additive with other item duplication effects.
• Duplicates all Unique items from every chest. This is additive with other item duplication effects.
• Duplicates every chest. This occurs after modifiers that apply to a random chest have already been applied.
• Triplicates every chest. This occurs after modifiers that apply to a random chest have already been applied.

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Dungeon Ability

Upon starting the dungeon, you have Burning Amber attached to you, which illuminates the area around you. Enemies outside of the illumination deal much more damage and take much less damage. You are also able to move the Burning Amber to a target location and recall it by activating your ability. This ability lets you target enemies but is also essential for burning pyres, which is necessary to progress through the dungeon and defeat the boss (more in the Boss section).

You can leave the Burning Amber attached to you, but being hit while it's attached results in the amber losing some of its illumination. The amount of illumination lost depends on how much damage is dealt. The illumination can be restored by slaying an Amber Elemental.

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Layout

The Lightless Arbor features several map layouts, all with a somewhat oval shape. In addition to these layouts, all dungeons have a system of pseudo-randomized roadblocks. These roadblocks change every time you run the dungeon, blocking some paths while leaving others open.

Each run consists of two different maps: one for each floor, followed by the boss, which is always in the same arena.

Enemies

While the normal enemies in Lightless Arbor are not especially dangerous compared to most enemies in the game, the large amounts of Poison Damage can cause issues for builds susceptible to DoT (Damage over Time) effects. Additionally, there are a few enemies with mechanics that need to be avoided in order to prevent taking excessive damage or being hindered during the dungeon run.

Enemies

• Rotweaver: The Rotweaver has the ability to Poison players from a distance with its Weave ability, which has no cooldown. A single Rotweaver isn't very threatening, but in groups, they can quickly take down players. Avoid accumulating too many stacks of poison by staying on the move, making it harder for them to target you.
• Rotting Hollow: The Rotting Hollow has three key abilities:
  • Biting Swarm: A slow-moving projectile that applies two powerful stacks of Poison.
  • Shockwave: The Rotting Hollow slams the ground multiple times, with each slam doing moderate Physical Damage.
  • Frenzied Thorns: A multi-projectile attack, with each projectile applying Poison and Armor Shred. All three attacks can be avoided by attentive players.
• Lightless Hive: The Lightless Hive continuously spawns Gloom Stingers, which are insects that apply Poison. When the Lightless Hive is destroyed, it explodes, dealing Physical Damage and applying Poison. Kill the hives quickly but stay out of Melee Range to avoid the explosion.
• Hollow Spriggans: Hollow Spriggans use a low Physical Damage attack, Thorn Barrage, to hit players from a distance. Their most threatening attack is Poison Cloud, which covers an area with Poison Damage that scales the longer the player remains inside it.
• Amber Elementals: Amber Elementals have two skills:
  • Fireball: A conal attack that deals low Fire Damage but applies multiple stacks of Ignite.
  • Upheaval: A line shot that deals moderate Physical and Fire Damage. While Amber Elementals aren’t especially dangerous, they are notable because killing them refreshes the illumination of Burning Amber.

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Difficulty

The difficulty in dungeons scales through Dungeon Tiers and Modifiers, with an added layer of complexity from the 'roguelike' aspect of dungeons.

Dungeon Tiers

Every dungeon has 4 tiers that you can choose from once they are unlocked. Tier 1 is available by default, and once you complete the dungeon, it unlocks Tier 2, and so on (Tier 2 of this dungeon will also unlock at level 65 if it hasn't been already).

Higher tiers feature higher-level enemies and stronger modifiers, making them significantly more challenging. Additionally, you need to complete higher-tier dungeons to obtain certain Uniques from The Mountain Beneath, as well as to unlock more modifiers for the Vaults of Uncertain Fate (see Dungeon Rewards for more info).

Modifiers

Selecting any Dungeon above tier 1 grants your first modifier. This modifier offers a certain reward but also increases the difficulty of the dungeon by adding Increased Damage and Increased Health to all enemies, including the boss. Additionally, you need to use two doors to progress through the dungeon: one to go from level 1 to level 2, and another to go from level 2 to the boss room. Each door also adds a modifier to your run from that point forward, making subsequent rooms more difficult but also more rewarding than the previous one.

Lower-tier dungeons have smaller modifiers, while higher-tier dungeons get substantially more difficult. For example, the strongest modifier at tier 1 adds 30% Increased Health and damage to enemies, while the strongest tier modifier at tier 4 adds 180%. When selecting your modifiers in a dungeon, don't just focus on the rewards it offers; make sure you can also handle the difficulty scaling.

You Only Get One Shot...

There are no extra attempts in Dungeons. If you die at any point during your run, you lose all of your progress and need to use a new Key to try again. You must balance the risks of starting over with the rewards offered to you, making sure you are prepared for each stage of the dungeon to maximize your experience and rewards.

Pre Boss Strategy

Whether you choose to clear the map or rush straight to the boss depends on the modifiers you pick up. For example, if you get a modifier that increases the drop rate of Exalted Amulets, it may be worth your time to clear the map. Keep in mind that higher-tier dungeons offer higher drop rates on modifiers, meaning that fully clearing lower-tier dungeons is unlikely to be as rewarding. It’s generally more efficient to push into higher tiers and farm there.

If the modifiers aren't enticing enough to farm the dungeon (and they often won't be), then there is no additional benefit to killing enemies in the dungeon. Your best strategy, if you can survive it, is to simply rush through the doors and get to the boss as quickly as possible. Every floor has two doors, so if the first door leads to a modifier that is not desirable or too difficult, you can look for the second door to see if it’s a better option.

Boss - The Mountain Beneath

The Mountain Beneath is a challenging fight with several one-shot or near one-shot attacks, as well as two distinct phases: The Mountain Beneath and Stone Titan's Heart. To successfully defeat this boss, you will need to understand his mechanics in detail, as failing to avoid certain attacks or properly react to phase transitions will result in instant death or significant setbacks.

Each phase has its own unique mechanics and requires careful positioning, timing, and awareness. Make sure to learn the patterns of his attacks and how to counter them effectively. If you are unfamiliar with the boss's abilities, it is essential to study and practice his fight to maximize your chances of success.

Mechanics

• Pyres: There are Pyres on the left and right sides of the arena that must be set on fire using Burning Amber. These Pyres are initially blocked by a Root Wall, which must be destroyed to access them. Once both Pyres finish burning, The Mountain Beneath will take damage, and upon the completion of both, he will transition into Phase 2.
• Falling Rocks: A large number of rocks fall from the sky, dealing moderate Physical Damage in a circle around their point of impact.
• Titanspawn or Mountain’s Roots: A single rock falls from the sky, dealing moderate Physical Damage in a circle around the impact. This also summons either a Titanspawn or three Mountain's Roots. The Titanspawn performs a melee attack that deals moderate Physical Damage, while the Mountain's Roots have a slam attack that does similar damage.
• Slam Attack: The Mountain Beneath slams the ground twice in quick succession, dealing very high Physical Damage that can one-shot most players. He always slams the left side of the arena first.
• Root Wall: A Root Wall travels from the right side of the arena to the left, dealing low Physical Damage and immobilizing players for a short duration.
• Falling Rocks (Repetition): A number of rocks fall from the sky again, dealing moderate Physical Damage in a circle around their point of impact.
• Titanflesh: Four Titanflesh are spawned. Each has a melee attack that deals low Physical Damage.
• Beam from Stone Titan's Heart: A beam is fired from Stone Titan's Heart, which splits into two and moves in opposite directions, dealing very high Physical and Poison Damage. The beams travel farther at higher tiers.
• Stone Circle: A large stone circles around the Stone Titan's Heart, starting close and traveling outward. The stone deals low Physical Damage.
• Energy Wave: Stone Titan's Heart targets one quadrant of the arena and fires a wave of energy at it, dealing low Physical Damage and applying 4 stacks of Poison.
• Root Engulfment: Stone Titan's Heart engulfs the arena with roots, leaving only the area closest to the heart as a safe zone. The roots deal low Physical Damage and immobilize players for a short duration.
• Thorn Barrage: Stone Titan's Heart fires several thorns in the general direction of the player. Each thorn applies multiple stacks of Poison.
• Mines: Several mines are placed on the ground, which grow in area of effect until they explode.

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Boss Strategy

There are two phases to the fight:

Phase 1: The Mountain Beneath

At the start of the fight, immediately head towards the right Pyre on the far right side of the arena. Starting on the right side will make it easier to dodge the first round of Shockwave. You need to destroy the Root Wall that is blocking the Pyre first. Once destroyed, place your Burning Amber on the Pyre and head towards the center of the arena.

• Rockfall: Try to avoid the Rockfall and kill any Titanspawn and Mountain's Roots while waiting for the first Shockwave. Once The Mountain Beneath uses Shockwave, he attacks on the left side first, so stay center-right to easily avoid it. As soon as the left side attack is over, immediately move to that side of the arena to avoid the right Shockwave.
• Left Pyre: As soon as the right Pyre is lit, recall your Burning Amber and head to the left Pyre. Take out the Root Wall and place your Burning Amber. Now head back to the center and repeat the step above. If you're fast enough in destroying the Pyres, there won't be a second round of Shockwave, but if not, you'll need to deal with it one more time.
• Once both Pyres are lit, The Mountain Beneath will fall over and you can enter the second phase through his mouth.

Phase 2: Stone Titan's Heart

Unlike The Mountain Beneath, Stone Titan's Heart is attackable and needs to be killed to end the fight, so deal as much damage as you can while avoiding his more threatening mechanics.

• Titanflesh: In this phase, Titanflesh aren't very threatening but should be dealt with when possible to avoid being overwhelmed by multiple damage sources.
• Spore Beam: The most dangerous mechanic in this phase is the Spore Beam. As soon as you see the beam, head to the opposite side. The beam won’t cover the entire arena, but on higher phases, it will cover most of it. Make sure your positioning is solid.
• Energy Wave: The Energy Wave does a lot of Poison Damage. You can either cleanse the Poison or avoid the mechanic altogether. Be aware that sometimes the safe zone for Spore Beam and the damaging area of Energy Wave can overlap, and the only way to avoid both is with a very well-timed movement ability or exceptional move speed (and some luck). Cleansing is the more reliable option.
• Other Abilities: All of the other abilities are either very well telegraphed and easy to avoid or deal low enough damage to not be especially threatening on their own. Avoiding Spore Beam and Energy Wave are the most important parts of this phase.

General Strategy:

The sheer number of mechanics in this fight and the distinct differences between the phases can be overwhelming for new players, but in reality, there are only a few mechanics that players need to learn to reliably defeat this boss. Understanding how the Pyres work and then avoiding Shockwave, Spore Beam, and Energy Wave are the keys to your success.

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Summary

• The Vaults of Uncertain Fate is a valuable gold sink that can only be accessed through this dungeon.
• Burning Amber is a dungeon mechanic whose usage is required to complete the dungeon and defeat the boss.
• Enemies are relatively easy, but be on the lookout for Rotweavers, Rotting Hollows, Lightless Hive & Gloom Stingers, Hollow Spriggans, and Amber Elementals.
• Dying in the dungeon causes the player to fail, lose all progress, and lose the Lightless Arbor Key they used!
• The Mountain Beneath is a two-phased fight with several mechanics you need to know to defeat him. Know how to destroy Pyres as well as how to avoid Shockwave, Spore Beam, and Energy Wave.