Thanks for the help, you are right, the problem was I had not saved Korg. I thought the object meant random orc, not the specific one detained in the cave by Succubus
Ah so it was Korg who wasn't saved yet. And no problem, glad to help. Btw a tip, you can return to the succubus again and find her second prisoner. (not related to this storyline, but for a different one)