Hello! I've also joined the game and Cyril will bet attaching himself to the group at some point, probably whether you want him to or not. He's not into slavery, but he is a merchant.
He does not really have his own sidequest planned, except that once he's figured out that everyone else is getting them, he might request a nice pie...and it had better be a really nice pie. Maybe he'll make one of the wardens bake it. And he can really milk this if he wants to.
Really, all he needs to jump on board is an opportunity, swinging by his shop for some thinly veiled plot reason should work.