I just had a thought: what if Will is not a sacrifice to release the demon, but rather a reincarnation of the demon that they've been raising so it won't be evil this time? That would explain the setup far better. If the demon is still sealed down there, there's no reason for them to be released from their duty — in fact, if there are demons bringing sacrifices to break the barrier, their duty is more important than ever. And why would the god say that their attachment is gone if Gus is still there and the demon is still sealed? And why was Gus attacking Will in earnest at first during the challenge? Makes sense if he was afraid Will had regained his memories.