Diablo 4's newest boss summoning item, Igneous Core, is your ticket to the Vault of the Loom and its boss: the Echo of Malphas. The robotic demon drops powerful loot for you and your construct companion, but takes a bit of preparation. If you're near level 100 and are in world tier 4, you'll need to cycle through the new seasonal activities in order to get a chance at fighting the season's big bad.

Igneous Cores were added to Diablo 4 after season 3's launch and replaced the old way of summoning Echo of Malphas, AKA “Uber Malphas”. You need seven Igneous Cores and 250 Shattered Stone to enter his lair, the Vault of the Loom. But if you want to open the bonus chests at the end for a chance at one of the two ridiculously powerful construct companion Tuning Stones, you'll want to bring four to five Pearls of Warding with you as well.

In your quest to obtain Igneous Cores, you'll come across plenty of other seasonal items, including the Shattered Stones you need and the Governing and Tuning Stones for your robot spider companion. Plenty of other players will be doing the same thing and will give you more chances at finding Igneous Cores.

How to get Igneous Core items

Here's the simplified loop for farming Igneous Cores, which I'll explain in detail below:

• Find and deactivate Igneous Obelisks in the open world to earn Elemental Cores
• Use three Elemental Cores and 50 Shattered Stone on Voltaic Braziers to summon a Herald of Malphas
• Defeat Heralds of Malphas for a chance to find an Igneous Core
• Repeat until you have seven Igneous Cores and enough Shattered Stone

Season 3's open world Arcane Tremors are the main source of Igneous Cores and you can always find them by zooming into different areas of the map. By roaming around and deactivating Igneous Obelisks, which are pillars that spit fireballs and red lightning, you'll collect Elemental Cores and Shattered Stone for summoning a Herald of Malphas at Voltaic Braziers.

The proper nouns make it sound more complicated than it is: You simply deactivate traps and then use the items they drop to summon a mini boss who has a chance to drop them (roughly a 25% chance). Then, you repeat that until you have enough Igneous Cores and Shattered Stone to summon Uber Malphas.

Ideally, you should do this loop in an area near braziers with red icons, which means they'll give you Grim Favors to turn in at the Tree of Whispers. Other players usually target these ones too, so you'll be able to loot Igneous Cores off of any Heralds of Malphas they summon while you're there.

Alternatively, Igneous Cores are a guaranteed drop off of the Son of Malphas boss who randomly shows up in Arcane Tremors and vaults—similar to how the Butcher can crash your dungeon. Son of Malphas is fairly tough and has a full boss health bar, so be careful if you run into him. Without a consistent way to find the Son of Malphas, you'll just have to do all the steps above to get your Igneous Cores.

How to get Shattered Stone

Season 3's new robotic construct enemies all drop Shattered Stones. As long as you follow the steps above and pick up everything on the ground, you'll be bathing in more than enough of them to summon Malphas. Running vault dungeons will shower you with them, too. 

How to use Igneous Core items for Echo of Malphas 

Here's a quick list of steps to farm Uber Malphas before my detailed explanation below: 

• Go to the Gatehall
• Head downstairs and enter the portal to the Vault of the Loom
• Spend four to five Pearls of Warding
• Interact with the Corrupted Altar to open the door to the vault
• Complete all four wings and enter the portal to the Malphas boss fight

To enter the Vault of the Loom, visit the Gatehall on the eastern border between Kehjistan and Hawezar (it's a blue gate icon). The entrance of the vault is down the stairs from the room with the waypoint in it. You can enter any time you like, but the locked door inside needs specific materials to open.

If you plan on running the Vault of the Loom, be sure to spend four or five Pearls of Warding at the Statue of Zoltun Kulle just before the Corrupted Altar near the locked door. Opening the door prevents you from interacting with the statue. You'll need all those stacks of buffs so you can afford to lose a few from running into traps on the way to and during the boss fight. When you're ready, interact with the Corrupted Altar and spend your seven Igneous Cores and 250 Shattered Stone to open the door. Groups only need one player to do this.

You'll need to make your way through four wings of the vault to find objects to place in the four corresponding pillars. Once that is finished, you'll find two small chests for one Zoltun's Warding each. Keep in mind, you need 14 Zoltun's Warding to open both of the bonus chests after the fight, so if you're running low, you might want to skip these.

The portal will take you to the boss fight against the Echo of Malphas. The fight takes place on a big disc and the camera will zoom out to give you a better view of the platform and the inevitable traps that will show up. Dodge out of his attacks and traps while destroying every pillar he spawns and you shouldn't have too much trouble with him.

When defeated, Malphas will drop his own loot, and then you'll be able to spend your Zoltun's Warding on two bonus chests. The Major Wardwoven Chest has a 3% chance of dropping the Evernight or Genesis unique Tuning Stones for your construct companion.