From Zero to Five Star Aditya

"Do you wish for power?"
Rio, a Zero Star, received an offer from The Devil.
The offer gave him the strength to fight against Arcdemon, the monster that terrorized humanity.
But there is one condition to get its strength, that there must be sacrifices that must be made.
A world where the human-representative Knights, Aditya, and monsters from other dimensions, Arcdemon, fought to fight over the earth. Rio Nugraha must be the strongest without having to rely on Devil's power.