|The World Event is a feature which was integrated to the game from Blizzard and its v1.10 patch. It normally appears only at realms but with a 3tr party tool „PlugY“, you can have this event in your Single Player games. |
A „Stone of Jordan“ Counter increases by a randomized timer and if it is high enough, the event begins. You only see this counter in hell games and so the event can only be triggered in this difficulty.
But note, that the Uber Diablo is a very strong boss monster and takes long time to defeat him, when alone.