Season 15 saw the addition of Moophisto, the Divine Bovine, as a summonable World Boss, but in order to access the Bovine Sanctuary and his altar, you will first need 5 Prime Ribs.
The original source of these Prime Ribs was the Cow King in the Secret Cow Level, but in Season 15, a new source has been added.
You will need access to Old Tristram for this, so check out our guide on how to unlock it.
In the northern part of Old Tristram, you will find the Cathedral from the original Diablo, and just outside it there will be a Wounded Townsman offering a quest to slay the Butcher.
The Butcher can be found in the first map of Diablo’s new capstone dungeon in Scosglen, The Labyrinth. Slaying him will drop 5 Prime Ribs, which can be used to unlock the Bovine Sanctuary.
With the Prime Ribs in your inventory, travel east from the Tyrael’s Encampment waypoint in the Celestia zone of Skovos.
There you will find the Altar of the Heifer, which will take you to the Bovine Sanctuary if you have 5 Prime Ribs in your inventory.
At the Bovine Sanctuary, you can find the altar to summon Moophisto, the Divine Bovine, as well as several Cow NPCs.
