In the NWN2 official campaign, characters may acquire a single stronghold. The stronghold begins as a shell, and players have to spend and gather resources to build and upgrade it how they see fit. That can involve searching the world for recruits, completing certain quests, or simply spending gold. How the PC takes care of the stronghold may have an affect upon the "good" ending. [1]
Strongholds are not class-specific [2] nor limited by alignment, although how they run their stronghold can reflect the titles they gain as history feats. [3].