About 1000 years ago, a war between the union of the Fairy, Human, and Beast races and the Demon Race broke out.
At the start, the Fairy Human Beast alliance dismissed them as disorderly mobs, but when push came to shove, the Demon Race had a higher sense of unity than they imagined.
The war finally ended in a draw, but considering the Demon Race's high individual skill and magic power, it was possible that the Fairy Human Beast alliance could have lost if the war dragged on.
Moreover, the Demon Continent is a country full of resources where minerals like ores, precious metals, magic stones, and gems were buried in great amounts.
They were discriminated against because their appearances were similar to monsters, but the Fairy Human Beast alliance came to know that they were a race that should not be made enemies of.
After the war, it became bad manners to treat the Demon Race with discrimination.