One of the most enduring legends within the Diablo series is the 'Cow Level'. Back in Diablo 2, shoving Wirt's Leg and a Town Portal Tome into the Horadric Cube would tear open a portal to a secret bovine realm, where you could face off against bipedal cows. While this tradition carried over to Diablo 3, it remains conspicuously absent in the latest entry, Diablo 4. Consequently, every time a new season kicks off, players embark on a frantic search, convinced that the 'Cow Level' is hidden somewhere in the depths of the game.

This trend persisted with the launch of Diablo 4 Season 11 on the 12th. While the 'Cow Level' remains elusive, a secret boss chamber has surfaced, capturing the attention of the community. In Diablo 4, the standard loop involves grinding for materials to summon bosses. However, this season introduces items with the 'Purified' prefix—body parts from the four major demons. Initially, their purpose was shrouded in mystery, but they are actually the keys to unlocking this hidden dungeon.

Here is the drill: you need to collect four specific items—'Purified Eye of Belial', 'Purified Tongue of Azmodan', 'Purified Horn of Duriel', and 'Purified Claw of Andariel'. Once you have these, head to the Altars of Sin located across different regions. Using these items at the altars will eventually trigger a red portal at the final one you activate. Stepping through pits you against all four demons in a single encounter. Defeating them rewards you with 'Resplendent Sparks' for crafting Mythic Uniques, Ancestral Uniques, runes, and various crafting materials.

It might not be the long-awaited Cow Level, but this unique method of unlocking a secret dungeon has certainly kept fans engaged. Furthermore, with the developers teasing the return of the 'Horadric Cube' for the upcoming 'Lord of Hatred' expansion—announced at The Game Awards 2025 on the 12th—the rumour mill is spinning again. Everyone is now wondering: will the expansion finally bring the Cow Level home?

Meanwhile, those who pre-order Lord of Hatred get early access to the new 'Spiritborn' class. As for the Season 11 'Divine Intervention' that went live on the 12th, it brings more than just the secret boss room; players can look forward to new content centred on the boss 'Azmodan', significant overhauls to Tempering and Masterworking, and a new 'Consecration' system to imbue gear with angelic power.