Avadon: The Black Fortress marks the inception of not only a new series of isometric CRPGs for Spiderweb Software (the previous two, Geneforge and Avernum, spanned 5 and 6 games, respectively), but also a new engine and artist. In Avadon, you play as a servant of the black keep, trying to unravel a conspiracy to destroy your people. The game features four character classes and multiple endings.
Like all Spiderweb games, Avadon has been released for Mac first, with a Windows version to follow in the next few months. The full version is $25, but there’s a demo of the game available to try out.
TIGdb: Entry for Avadon: The Black Fortress