Over the weekend, I spent approximately three hours farming the materials and the 150,000 gold required to enter the secret level in Diablo III. It was kind of a pain, but it was completely worth it to be able to send three of my friends in utterly free of charge, and enjoy it with them before most of it was sufficiently spoiled.
Because most of the guides I’ve found aren’t particularly concise in their directions, and provide spoilers to boot, I’m going to make a completely spoiler-free guide on how to access the secret level itself.
1) The Basics: you need five reagents to build the staff to access the secret level, in addition to the recipe to build the staff itself.
The recipe is found in Act 4 near the very end of the game, so I suggest beating the game on Normal (you should be around level 30), then clearing all of these areas with your high-level character. It will be much easier to do so.
2) Act I: The first item is the Black Mushroom. You can find this on the first floor of the Cathedral in Act I, but it will not spawn every time. Take the Cathedral Gardens waypoint and walk left towards the Cathedral, falling down into it as normal. Put on your fastest movement gear/passives/skills and run around until you find a Black Mushroom growing on the floor.
If you don’t, quit the game and hit “resume game”, repeating the process. It took me around 10 runs to find it, so don’t give up.
3) Act I: The next item is Leoric’s Shinbone. This is one of the easiest items to grab, but one of the least likely to spawn. Take the Leoric’s Manor waypoint in Act I. When you enter the Manor itself, you’ll be greeted with around 30 minions.
Run past or eliminate them, and head to the first door on your right. At the end of the room you’ll find an unlit fireplace. If you can click on it, Leoric’s Shinbone will pop out. If not, leave the game, and resume to try again.
4) Act II: Wirt’s Bell is the easiest to get.
All you need to do is find Squirt in Act II at the Caldeum Bazaar near the South-West tip of the town. Buy the bell for 100,000 gold.
5) Act II: Liquid Rainbow is next. Enter Act II and take the Path to the Oasis waypoint. Go completely south until you find a shack with Zaven the Alchemist near it. If he doesn’t spawn, leave the game and resume until you find him.
Once you save him from attack, enter the Mysterious Cave. In this cave, you may find the Mysterious Chest on either the first or second floor. It’s not a guaranteed spawn, so keep leaving and resuming until you find it — if Zaven doesn’t spawn, you have to try it again.
6) Act III: The Gibbering Gemstone in my opinion is the hardest piece of the puzzle. Take the The Bridge of Korsikk waypoint in Act III and go up to reach the Fields of Slaughter. In the Fields of Slaughter, one of two caves can spawn. The Icefall Caves or the Caverns of Frost. You want the Caverns of Frost — if the Icefall Caves spawn, leave the game and resume to try again.
If you spawn the Caverns of Frost, enter it and find a unique enemy called Chiltara. It’s a cat-like unique purple creature. Kill it to obtain the Gibbering Gemstone. This took me around 20 attempts to do, so be prepared.
7) Act IV: Finally, the plans are within your grasp. Enter Act 4 with the Gardens of Hope Tier 2 waypoint. Clear the one room required and fight the second boss (to avoid spoilers, it’s the one fought right before the final boss in a circular arena).
The boss will randomly drop the plans.
8 ) Once you have the plans, give them to the blacksmith to gain the ability to craft the Staff of Herding for 50,000 gold.
9) Take the staff in-hand and go to the very first town in Act I (New Tristram). Go out the right gate and head North until you reach a left-bend — head up the road and you will see the ghost of the Cow King. Talk to him to enter the crack in the ground, and enjoy the secret level!
In Nightmare Mode, you’ll need the Nightmarish Staff of Herding. Buy it from Gorell the Quartermaster in Act 4, and you’ll be able to craft the Nightmarish Staff with the original staff and 200,000 gold.