The portal to Sho’guul’s lair has a chance to be spawned when first entering the room with an exit hatch.
Sho'guul's portal-spawning mechanic is based on mathematics between Blessings and Curses.
Every run the percentage chance to encounter Sho'guul is set to 5% at the start of Goldmine 1. The chance you accumulate carries over floors in a single run.
Obtaining curses grants 10% per major curse and 5% per level of minor curse.
Obtaining a blessing, whether through the use of Inverter, through Altars, or picking them up from the ground, removes 5%.
Blessings granted by the Censer do not count towards this calculation.
Removing curses, whether through Penance, the Purge or Purification potions, Talismans, or otherwise does not reduce the chance to encounter Sho'guul.
Leaving Sho'guul's floor resets the chance -15%, even if you do not buy anything from him.
You can encounter him more than once in the same run, but due to the mathematics explained above, doing so requires both luck and active curse stacking without getting a corresponding number of blessings.
The entrance to his shop will not disappear if you leave the room.
Legendary items available for deals can not be transmuted. Any items dropped as a result of taking one of his deals can be transmuted, but not into other legendary relics.
Sho'guul's dialogue lines vary based on the amount of curse the player has.