When the Xiles Kingdom was losing the war against the demon, the population claimed for the hero summoning ritual. The king Icarus ignored their claim and decided to lead the world's army himself. Thanks to his wisdom and powers, the people of the world managed to slay the demon king without relying on heroes and thus emerged victorious. However, since the king was the one who dealt the finishing blow and was covered by the demon king's blood when he did it, he received a curse… the curse not to take the demon's king seat, but to become something even more dangerous: a demon god. They also have a time limit to save the world, just eleven months before the demon god reaches the pinnacle of its strength.

After losing their best warrior and strategist, the people of Xiles Kingdom decided to summon the heroes after finding an ancient prophecy that only the cooperation of the two heroes would prevent the world's ending. They succeeded in the ritual, but there was a problem, the heroes didn't want to work together because they were once a couple and one that liked to argue a lot...