In Resurrected, this meant ignoring the king when you saw it on the map, but this is no longer the case.
In the original Diablo 2, the most important thing to remember was not to kill the Cow King because you wouldn’t be able to open the portal on that difficulty level again. This means you’ll have to finish Act 5 before you can play on Normal difficulty, and the same is true of Nightmare and Hell. You won’t be able to open the portal until you’ve completed the game on your chosen difficulty level. When you use the cube, it will open a portal to the Cow Level in Act 1’s Rogue Encampment.
You’ll need Wirt’s Leg as well as the Tome of Town Portal to open the Cow Portal. The first time you use the cube, it will be to rebuild the Horadric Staff, which will demonstrate how to use it. You’ll find this item in Act 2’s Halls of the Dead, and you’ll need it to complete a quest, so it should be easy to come across. All you need now is the Horadric Cube and the leg. Tristram has a lot of tough enemies, but if you’re just here for the leg, chances are you’ll be able to handle whatever you come across. Wirt’s Leg can be found on Wirt’s corpse in Tristram, and it can be accessed by interacting with the Cairn Stones and passing through the portal.
