'Monster King.' A being that landed in the tallest mountain of the world Haria from the sky, one-hundred fifty years after the reign of the Tyrant Demon Lord ended. It is a powerful being capable of evolving and enhancing all existing monsters using the 'mist' it spread throughout the planet and its every other realms. A normal slime that even a normal villager could defeat will now take at least ten level ten adventurers. No one know who called it "Terrestrialization Virus" nor do they know where it came from, everyone started referring to the 'mist' with that name. This resulted in making the Summoners and Beast Tamers into 'useless class.' Fortunately, the Descendants of The Seven Heroes that defeated the Tyrant Demon Lord managed to seal the Monster King and weaken its influence all over the world and realms. Now, our Summoner, who only had one goal on his mind; to be as powerful as his father, will now defeat the Monster King due to various circumstances that even he does not understand.