With the Skyrim universe, you could really work with that. Even the Oblivion universe. Imagine we're angels fighting the war in heaven while Satan is actively bringing angels over to his side.
The war would end with Satan taking his followers and trying to square off against God, and you could be on the side of Michael and other angels fighting him back.
Maybe there could even be a choice to refuse Satan as he tries to convince you to follow him. If you choose not too, you do quests for the angels not choosing to follow. If you choose to follow Satan, you do quests for his side.
Maybe, you can choose to be on the good side, but if you commit crimes, somewhere along the way, it will turn out you're following Satan and didn't realize it.
Then after Satan and his followers are cast to the earth to roam to and fro, if you chose their side, your job will be to deceive humans. If you didn't, your job will be to protect the faithful and to a lesser extent, the unfaithful from the deceptions of Satan's forces.
This would mean that while you may permit them to tempt the human, you can never allow them to take it too far. If they try to take it too far, you must fight them back. If you're unsuccessful, you reappear somewhere and must get back over there to keep them from taking that person into deeper sin. There can be like a timing on it. The longer they remain unresisted overstepping what they are permitted to tempt, the more likely that the person/s will be brought further into sin. Of course, don't make the sins graphical. It can all be processed logically, I'm sure. Maybe an indication that implies what the sin is so that you know in what direction they're headed if the demon becomes more successful.
The war would end with Satan taking his followers and trying to square off against God, and you could be on the side of Michael and other angels fighting him back.
Maybe there could even be a choice to refuse Satan as he tries to convince you to follow him. If you choose not too, you do quests for the angels not choosing to follow. If you choose to follow Satan, you do quests for his side.
Maybe, you can choose to be on the good side, but if you commit crimes, somewhere along the way, it will turn out you're following Satan and didn't realize it.
Then after Satan and his followers are cast to the earth to roam to and fro, if you chose their side, your job will be to deceive humans. If you didn't, your job will be to protect the faithful and to a lesser extent, the unfaithful from the deceptions of Satan's forces.
This would mean that while you may permit them to tempt the human, you can never allow them to take it too far. If they try to take it too far, you must fight them back. If you're unsuccessful, you reappear somewhere and must get back over there to keep them from taking that person into deeper sin. There can be like a timing on it. The longer they remain unresisted overstepping what they are permitted to tempt, the more likely that the person/s will be brought further into sin. Of course, don't make the sins graphical. It can all be processed logically, I'm sure. Maybe an indication that implies what the sin is so that you know in what direction they're headed if the demon becomes more successful.