Diablo 4 Season 9 Lair Boss Key Farming Guide: What's The Fastest Way To Collect Them?
Posted: Aug 04, 2025 Views: 296
For players reaching Endgame, farming for unique and mythic gear is essential to complete your build. Unique gear is easier to farm on Torment 4 difficulty, but the drop rate for mythic gear is very low.
Aside from crafting with Resplendent Sparks and Diablo 4 Runes, farming Lair Bosses is a common method. The catch is that to get Lair Boss rewards, you must first collect Lair Boss keys.
Lair Bosses
Lair Bosses have undergone some changes in Season 8, with the addition of a new boss, Belial, and the tiers of bosses being divided into three levels: Initiate, Greater, and Exalted.
Unlike previous seasons, you no longer need Lair Boss keys to Initiate boss fights, but you will need the corresponding Boss Keys to get the rewards. If you’re playing with others, everyone needs a Boss Key to open the chest after defeating the boss, and sharing is not allowed.
The rewards for Initiate Bosses include Boss Keys for Greater Bosses. After defeating any Initiate Bosses or Greater Bosses, there’s a chance you’ll encounter Belial’s Ambush. After defeating this sudden boss, it will drop Diablo 4 Betrayer’s Husk.
Here are the required keys and drops for all lair bosses:
Initiate Boss
- Varshan: 12x Malignant Heart (Requirement), Shard of Agony or Stygian Stone (Drop)
- Grigoire: 12x Living Steel (Requirement), Shard of Agony or Stygian Stone (Drop)
- Beast in the Ice: 12x Distilled Fear (Requirement), Pincushioned Doll or Stygian Stone (Drop)
- Lord Zir: 12x Exquisite Blood (Requirement), Pincushioned Doll or Stygian Stone (Drop)
- Urivar: 12x Judicator’s Mask (Requirement), Abhorrent Heart or Stygian Stone (Drop)
Greater Boss
- Duriel: 3x Shard of Agony (Requirement)
- Andariel: 3x Pincushioned Doll (Requirement)
- Harbinger of Hatred: 3x Abhorrent Heart (Requirement)
Exalted Boss
- Belial: 2x Betrayer’s Husk (Requirement)
How To Farm Lair Boss keys?
Relying on killing bosses to get keys for other bosses is inefficient, but thankfully, there’s more to it than just that. With the exception of Betrayer’s Husk, every material has other drop sources.
Here are the farming paths for each boss material:
Abhorrent Heart
- 1. Undercity of Kurast (Tribute of Titans)
- 2. Urivar
- 3. World Bosses
Betrayer’s Husk
- 1. Belial, Lord of Lies ambush encounter in Lair Boss
Distilled Fear
- 1. Kurast Undercity (Tribute of Titans)
- 2. Nightmare Dungeons
- 3. Bartering
- 4. Tree of Whispers
- 5. World Bosses
Exquisite Blood
- 1. Kurast Undercity (Tribute of Titans)
- 2. Blood Maiden (Helltide)
- 3. Bartering
- 4. Tree of Whispers
- 5. World Bosses
- 6. Legion Events
Judicator’s Mask
- 1. Kurast Undercity (Tribute of Titans)
- 2. Kurast Undercity (without Tribute of Titans)
- 3. Bartering
- 4. Tree of Whispers
- 5. World Bosses
Living Steel
- 1. Kurast Undercity (Tribute of Titans)
- 2. Helltide
- 3. Bartering
- 4. Tree of Whispers
- 5. World Bosses
Malignant Heart
- 1. Kurast Undercity (Tribute of Titans)
- 2. Tree of Whispers
- 3. Bartering
- 4. World Bosses
Pincushioned Doll
- 1. Kurast Undercity (Tribute of Titans)
- 2. Beast in the Ice and Lord Zir
- 3. World Bosses
Shard of Agony
- 1. Kurast Undercity (Tribute of Titans)
- 2. Grigoire, the Galvanic Saint and Echo of Varshan
- 3. World Bosses
Kurast Undercity And Tribute
Among the above methods, Kurast Undercity is the most efficient dungeon, but it’s included in Vessel of Hatred, released in Diablo 4 season 6. This dungeon has a countdown, and you can extend the duration by killing monsters. The longer you persist, the better the rewards.
You can use Tributes in advance to change the rewards in Kurast Undercity. The rewards for different tributes are as follows:
- Tribute of Pride (magic): Legendary items
- Tribute of Mystique (magic): Magic runes
- Tribute of Titans (Rare): Boss summoning items
- Tribute of Refinement (Rare): Masterworking materials
- Tribute of Harmony (Rare): Runes
- Tribute of Radiance (Legendary): Ancestral legendary items
- Tribute of Ascendance (Unique): Several unique items, and increases the chance of receiving a Mythic unique item
Tributes can be gotten in a variety of ways, including defeating bosses and farming The Pit and Helltide. If you need to farm Obducite, replace Tribute of Titans with Tribute of Refinement. If you’ve accumulated a lot of Tribute in your inventory, use it quickly to convert it into resources.
Which Lair Bosses Are You Targeting?
The reward pools for different Lair Bosses vary. If you’re farming Mythic items, Duriel, Andariel, and Harbinger of Hatre have higher drop rates, so you can target them to collect the corresponding keys.
The highest drop rate is from Belial, but since collecting Diablo 4 Betrayer’s Husk is more difficult than with other bosses, it’s not as efficient.
This is a general guide to farming Lair Boss keys in Diablo 4 Season 9. The most recommended method is to farm Kurast Undercity. If you don’t have the DLC yet, it’s highly recommended that you unlock it. The runes, mercenaries, and other unique content included in Vessel of Hatred are key ways to increase the strength of your builds, while Kurast Undercity is one of the best dungeons in Endgame for farming various materials.
Recommended Article
-
Diablo 4 Season 9 Best Infernal Horde Farming Strategies: How To Harvest Burning Aether Efficiently?
-
Diablo 4 Season 9 Stormclaw Druid Build After Patch 2.3.1: Why Has It Become Stronger?
-
Diablo 4 Season 9 Obducite Farming Guide: What's The Most Efficient Method?
-
Diablo 4 Season 9 (4 Tips For March Of The Goblins Event): How To Maximize Rewards?
-
Diablo 4 Season 9 Rune Farming Guide: What Else Do You Need Besides Luck?
-
Diablo 4 Season 9 Final Review: It Won't Get Any More Big Updates