OK! You go to act 5, to cube the 3 keys. Then you go into the portal, and kill an Lillith. She dropped Diablos horn for us. So far... thats it. We're going to get the keys again and do it again.. see if we get Mephs brain, or Baals eye.
Oh and btw. The enemys are FUCKING strong! LoL. Like hella strong, they almost killed my hammerdin, and it takes him like 5-6 11K(w/out GC's) hammers to kill one of those bitches that fly around w/ the wings. Forget the names.