Okay, firstly, this system won't be like every other leveling system. In a way, it is, but everyone receives it, not only the MC. Also, the MC will not be op and will face very tough challenges and have many losses. The aura farming moments will be peak, I can ensure.
Basically, if you are a demon, you can spawn your own demonic weapon through rage. Once you acquire a demonic weapon, it makes a system for the user, an interactive system. And that works for demons only, and will be working for Zylus. Whilst all this is occurring, it will work similarly to every other leveling system. But there will be many twists. If you read, I promise you will enjoy. Have fun!
(Don't want to spoil too much, read as the power system progresses)