The Traitor's Wake - Main quest | Forlorn Cliffs / Darklake District Walkthrough Sword Coast Legends Guide

After the conversation with the Succubus, defeat the summoned demons. Head towards the lower parts of the Overlake Ramparts, and kill the groups of charging demons. At the end of the location, you notice a tunnel - Darklake tunnel, which takes you back to Darklake District. At the end of your path to the main part of the district, you spot the imprisoned succubus (M11,Succubus). Your task is to decide its fate. You can leave him to death in pain (select Celestial Stone) or banish him to hell, which will be an act of mercy (select Infernal Stone). Regardless of your choice, go to Tezzarae's camp in Forlorn Cliffs. After you get there approach the pedestal and put the Belaphoss' stone (replace it for the one thereto open the portal to his realm).

Note! The decision to cross the portal is irreversible. If you do that, you will no longer be able to return, so it is a good idea to tie up all of the loose ends and side quests, before you enter Belaphoss's portal.