Living Steel is a summoning material in Diablo 4 that is used to summon the endgame boss Grigoire, The Galvanic Saint. This boss not only rewards anyone who defeats him with incredible loot, but he also drops other summoning materials. So, getting and using Living Steel is super crucial in the endgame.

You can obtain Living Steel from the Tortured Gift of Living Steel chest in Diablo 4's Helltides. The source also drops randomly after defeating Elites, Hellbornes (Helltide), and the Blood Maiden (Helltide), or you can collect it by participating in Events like Legion and World Boss, finding Treasure Goblins, and opening Whisper caches.

As you can probably guess, the best and fastest way to get Living Steel is through Helltides, which run every hour for 55 minutes and then take a five-minute break. Once the time is up, it will reappear in a different area of the map and you can enjoy the Helltides for another 55 minutes. It’s pure chaos and can be a lot of fun. If you’ve never participated in the Helltides, you’ll know you’re in a Helltide area when it’s highlighted in red.

To open the Tortured Gift of Living Steel chest, which gives around five Living Steel, you’ll need to earn 275 Abberant Cinders. These can be obtained by killing enemies in Helltide events. I’ve also received Living Steel from other Tortured Gift chests (around one per chest in World Tier Four), so this might also be a good option if you’re short on time and need to spend Cinder quickly. They don’t roll over into the next Helltide.