There are 2 phases:
first u cube the pulsating worldstone shard with:
- Assur's Bane
- Sigil of the 7 Deadly Sins (aka, void ring)
- Glorious book of Median
- Mystic Shard
- Neutrality pact
This last one REPLACES Uldy's sword. He no longer drops this but instead drops the pact. U need to cube this instead.
Then, u get a Pulsating Worldstone Crystal
Also, the items listed above will get consumed. so you lose the charms and rings. However, you only need to make the crystal once. U can reuse it in the next step:
The crystal needs to be cubed with:
- 4 greater signets of learning
- the 3 Fautz Greatrunes
This wil finally net you a scroll opening the portal to Samael;