How to Unlock Boss Powers
There are two primary ways to Diablo 4 Items unlock Boss Powers:

1. Defeating Seasonal Bosses
Each time you defeat one of the featured bosses for the first time, you’ll unlock their Boss Power. These bosses are spread across various activities, including the reworked Boss Ladder and special events.

2. Apparition Incursions
New to Season 8, Apparition Incursions are timed boss rush-style events that take place throughout Sanctuary. These events spawn Apparition Monsters, which when defeated, trigger a battle with one of 10 Apparition Bosses. Defeating them grants their Boss Power—and you might even get a chance to face Belial at the end of the incursion.

These events can be completed at any difficulty and offer an early path to acquiring Boss Powers before entering higher-end content.

The Revamped Boss Ladder and Belial’s Influence
Season 8 also reworks the Boss Ladder system, making it more accessible and rewarding:

Starting at Torment difficulty, you can now challenge bosses without needing summoning materials.

The old summoning items are now Lair Boss Keys, which are used to open loot chests after boss fights.

Stygian Stones return and can now be converted into Greater Lair Boss Keys for more powerful bosses like Duriel, Andariel, and cheap Diablo IV Items the new Harbinger of Hatred.