Things You'll Need
Instructions
Place one of each type of key into the Horadric Cube and click the "Transmute" button. The Horadric Cube takes the keys and opens a portal.
Enter the portal and fight the first boss, Uber Izual. Once defeated, Uber Izual will drop Mephisto's Brain. Pick up the brain.
Place one of each type of key in the Horadric Cube again and click the "Transmute" button. This, like the first time, will open another portal.
Enter the portal and fight the second boss, Uber Duriel. Once defeated, Uber Duriel will drop the second organ, Baal's Eye. Pick up the eye.
Place one of each type of key in the Horadric Cube again and click the "Transmute" button. This will open the third portal.
Enter the new portal and fight the third boss, Lillith. Once defeated, Lillith will drop the third organ, Diablo's Horn. Pick up the horn.
Put the three organs into the Horadric Cube and click the "Transmute" button. This will open the last portal that leads to Uber Tristram.