The Ranger Túgonn has told you that the door into the central area of Ost Dunhoth is locked and can only be opened by exploring the side wings.
'Each of the Gaunt-lords you defeated held mastery over a particular facet of the offensive planned by Gortheron: Thadúr the Ravager, master of poison; Ferndúr the Virulent, master of plague; Drugoth the Death-monger, master of fear. You did not encounter Ivar the Blood-hand, but he is the master of war.
'Together, with Gortheron, they are five. Five Gaunt-lords made in mockery of the five Wizards. Gortheron has corrupted these sprawling ruins, making of them a home for the servants of the Gaunt-lords.
'The door into the central area is sealed; if you are able to defeat the minions of Gortheron in each of the side wings, we may be able to open the central area and challenge Gortheron directly.'
Ost Dunhoth has two wings that must be explored before the central area can be unsealed.
Túgonn is in the entrance of Ost Dunhoth.
You have conquered two wings of Ost Dunhoth and should return now to Túgonn.