Mana is a form of natural energy that radiates from anything of magical nature, including Hunters, Magic Beasts, and Gates.
Description[]
Mana is not native to the human world. Instead, it originates from gods such as the Absolute Being and their creations, such as the Rulers and the Monarchs. As a result, humanity was not aware of its existence until gates, portals from another world, started opening up around the globe.
The flow of mana into the human world through the gates is what caused certain people to awaken and become hunters, as it would integrate into their bodies and grant them magical abilities. It should be noted that once a person awakens, the mana flowing through them strengthens their bodies to the point that conventional human weaponry cannot easily hurt them. As a result, even the weakest hunter is significantly more durable than an ordinary human.
The amount of mana emitted by a hunter can be measured into a numerical value with special devices and the corresponding measurement is how they are categorized into the ranking system. The only exception to is are S-Rank Hunters, whose mana output is too high for these devices to accurately measure. There are also rare cases of hunters being able to consciously control their mana output and conceal their true abilities so that they can rank lower than they should; these hunters are called False Rankers.
Mana can be found in inanimate objects found inside the dungeons, such as Mana Crystals and essence stones. After the gates first opened, it was discovered that they could used as a clean and long-lasting power source, eventually making it possible for hunters to sell them on the market for large profits.
However, despite the fact that people are awakening almost every day, some humans have a lower tolerance to mana; this prevents them from awakening and ever becoming hunters. There are also people whose bodies cannot tolerate the existence of mana and can develop a sleeping disorder called Eternal Slumber if they are exposed for too long. Due to the fact that humanity still lacks knowledge on the practical applications of mana, there is no known cure for Eternal Slumber. As a result, it is essentially a death sentence for those who are diagnosed with it.
As later discovered by Sung Jinwoo, the Rulers were the ones who created the gates for the sole purpose of filling the human world with mana. This would reinforce the earth for their coming war with the Monarchs and ensure that humanity wouldn't be completely wiped out by the time the bloodshed was over.