After we wander further into keep, we see more skeletons and ghosts, but they less hostile. Especially after devil girl say "lux". I guess skeletons no understand me because me say words too fast. One ghost pointed out a hidden compartment in a room, containing book. It diary of Ferrin Martinez that talk about what happened on island, it also contain words from before, including whole version of third word. 

Devil girl figure out word passcodes: Lux for interior, shestnik for arrival, samsoud for departure. We go to basement, which full of scary presence. We also figure out perhaps keep attacked by people who dig in from underdark. We also find vault room with three big doors, with one opened. It go to weird shaped room with mysterious pedestal that seem like something taken from it.

Then we head up upstairs, where we find ghost of Martinez. Devil girl talk to him, and tell him what happened to city, and he say something about three great generals, men who wielded great power and control: Edranka, Torath and Tyranthraxus. They were in charge of the Black Horde that destroyed Phlan. Also, Great Sage Mendor who founded a library in the Old City. It was known to be a center for learning in the area. But yeah, last Martinez heard, he was trying to collect info on the forces besieging Phlan. Oh, he was also very upset when he heard one of the vault doors was opened.

We tell him to rest and he fade away. We continue to search castle, but when we get ready to go, we see bunch of orcs charging castle at us.