Ok so we just started running this campaign last night, and when my pcs were being given the tour they found the pit and as one of my characters used to be a slave he was bothered by the fact that goblins, being a sentient race were being used for bloodsport. He promptly picked up Saul and threw him into the cages. Saul is now dead after being torn apart by goblins. Any suggestions on how to further the campaign at this point?
Second Darkness is one of those hard to keep on track campaigns. I think you might have to do some conversions, but if the party is good you could go from that "cleaning up a bad area of town" angle. It's been a while since I read the material, but let some thugs come in and try and take over the place and let them know that if they don't make a foothold in the city it will never get better.
What's the next step in the plot?
The next step was supposed to be them working in the Golden Goblin for a couple of days until it took long enough to notice something was up. Saul was supposed to give them a couple of jobs and then send them to the ambush
Riddleport is a place where might makes right and possession is 10 tenths of the law.
Easy enough to say the PCs now own the goblin outright -- if they can keep it. Many of the same "missions" could still happen, based on Saul's creditors comingt to call or things that other staff tell the PCs about.
Thats pretty much the conclusion I've come to after spending most of the time since thinking about it
I've recently just started running Second Darkness myself (actually only about 3 sessions in at the moment).
With Saul out of the picture you have a couple of options in my view. With the way Riddleport is run, whoever finds the deed to the Gold Goblin becomes the owner. So once some of the other crimebosses figure out Saul is no more (which in a town like Riddleport shouldn't take too long) they will come looking to claim the territory. This could lead to your group having to either defend the casino from others or join up with another crime boss.
The other thing you have is the fact that Saul's "boss" now doesn't have anyone working for them and helping them on the surface. Eventually they will come up to see why things aren't happening or try to install someone else in Saul's place.
Any way you go, the missions that happen can still be used, just have to change who gives them. Larur (the floor mananger) is a likely candidate since it seems like he'd be the most likely to try and keep the Goblin running after Saul's death.
Have they also killed Bojask? If not, you could establish him as a recurring villain to harass the party.
The biggest problem you now have is introducing the drow, who are allied to Saul and operating out of the sea caves beneath the Gold Goblin.
My advice would be to have Clegg Zincher and Boss Croat move in on the group's New casino. Try to keep Zincher alive as he is pivotal to book 2, but Croat is expendable (just reskin Saul's stat block?). Maybe the PCs ally with Zincher against Croat, an alliance of convenience. Then you could still shoehorn in some of the set pieces from the book as written (like the ambush in the saltmarsh).
Have Kwaya investigate the PCs, suspecting they are allied with the drow. With Saul dead, the payments to the drow will dry up and they will probably come looking for Saul. Maybe the drow send a representative to give the group a business proposal.