Peregrine

Just thinking about a new kind of menace for future Avernum games, that would fit in with the underground theme, how about some kind of slime or algae that was mutated by a magical experiment, and now it has the ability to turn part of itself into duplicates of creatures that it kills. This could be worked into the game in a small way (a side quest where goblins or bandits are turning into green goop when slain) or in a larger way, where the hive mind or master slime that is intelligent and controlling some large plot has to be tracked down and destroyed.

Instead of trying to make scenarios without Bob, which certainly can be done, I think it's good to make Bob as interesting as possible. Think about the Crones in Nethergate. They give the party quests and explain things, but they're a key part of the plot and are pretty interesting. I haven't done any Blades scenarios, but one twist I've used with Bob in my PnP games is what I call "Riding the Tiger" Bob (or whoever.) Bob has done something bad. He still might be an official/spellcaster/military leader, but he has been stealing from the government and is trying to cover his tracks/has summoned some kind of nasty creature which may be trying to kill him/has been corrupt and incompetent and has let a situation in his area get out of hand. Bob is screwed, unless he can get the party to help bail him out of the situation. Bob will lie, manipulate, and lead the party on as much as he can. Of course if the party ever finds out they're being used, Bob is in real trouble. Same if the government/demon/higher-ups find out what's going on. He's riding the tiger, if he stops he's going to get eaten. You can get some really interesting results with this kind of Bob.