1. Never underestimate how far a demon will go against its enemies. Rogue demons went against hell and because of that, they had their power revoked and thus began to help the humans. Now even if it is for their own selfish needs, a demon will work with just about anyone if it means getting what they want.

2. Magic can only be used by demons and those hat are higher. Angelics have an advantage because they can wield holy artifacts which demons can't even touch without it burning them. Now it is possible that you would be able to come across a relic that could allow you to cast illusions but for the most part, you wouldn't be able to do them yourself.

3. Ok