Just defeated the Black Monolith. In the end I had 6 (!) people with whips trying to disarm The Conqueror (most of these men had 95% chance to hit). None succeeded over 3-4 turns.
Is this a bug? Is The Conqueror supposed to be immune to disarm?
Yes, he’s immune. When targeting him with the ‘Disarm’ skill, the tooltip will tell you so, just like it tells you that Orc Warriors are immune to being stunned.