Soul of Evil becomes immune

Uber Diablo won’t spwan his adds ad 75% health and becomes immune. Not too much of a deal, but annoying…

Having trouble deciphering this sentence.

If you are playing D3: Uber Diablo only spawns in a portal that can be opened in the house at the top New Tristram. You bust open the door and get an entry way to the Heretic Abode. You need the Infernal Machine from the key warden in act 4 to open the portal.

If you are not playing D3: You need to post this on that game’s forum. (Thinking this might be a D2R issue).