Could someone who's played the Enhanced Editions indulge my curiosity - how the Black Pits areas fit into each game? From what I've read I get the impression that they're not part of, or accessible from, the main games at all. Is that right? If so (or if not), how do they fit in and how do you access them?

I only played it on BG1:EE. You can think it like a separate side game. When you start the game you can either play normal game or Black Pits. In Black Pits, you crate your own party and fight arena battles. You return to the shop after defeating each battle. You may encounter the character on Black Pits in the game but he was annoying so I killed him :)

Thanks.