70 years ago, a portal to another world opened, and humanity set foot in a completely different world. During their exploration, humanity encountered various other races, including their own, other races of humanity in other worlds.

Several years have passed since the portal first opened. The two worlds decided to reconcile and accept each other, complementing and sharing knowledge, sharing territory, and sharing credibility within their two worlds, and an inter-racial facility center was established on Earth and in other worlds, known as "Aurora."

Politics and laws also changed. Over time, more and more races and other intelligent beings joined the inter-racial facility center. They all had membership cards, and races with a certain level of intelligence also joined.

The peak races of intelligence, almost identical in appearance, were the Elves, Half-Humans, and Dwarves. They looked identical to the human race on Earth, but possessed various unique characteristics that distinguished them.

The Oni Race They are also a race with average intelligence, social skills, and have abandoned their savage nature, becoming a superior race that is now equal to other races.

As both parties developed, interracial marriage was finally legalized, and various half-races began to emerge, fulfilling their diversity.