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.
