In the memory of this boy, the world where I have reincarnated is a world of 250 floating continent and the main world is described to be endless. In this world once there was peace and prosperity in the continent until human started to desire to concurred each of the continent, war started happening around every continent. Watching bloodshed of there own creation many god's started protesting among then. Due to which some god created a taboo called black magic and attacked humanity, the God's who supported humanity started protecting us from them and this was the reason why two faction called light and darkness was born.
Soon the followers of dark god started using black magic and believed that every continent should be controlled by single supreme ruler that's how this war will come to an end.
God's of the light faction started giving there guide to make human entering into evolution phase where these human can have a chance to become Angeles and God's if they gain certain amount of blessings from people.
Soon thousands years has passed and the is still on progress and a new profession called adventurer started.
The dark beast collect pure amount of energy of heat, water, air, lightning are collected and formed into core to develope it's body into a powerful beast, the bigger the core the more powerful will be its power and capabilities.
These core can be used for creating fire water and electricity to run various simple machine's.
These core were used to create weapons for adventurer and other soldier, they were also used for cooking, washing etc. Hence adventurer gain money through these methods of selling core of a powerful beast, they get money through quest and get protection of wealthy people.