A world where demi-humans such as beastfolk and demons exist alongside humans. However, humans stand at the top of the world, treating other races like animals. Deprived of human rights, they are bought and sold as livestock or pets. One day, a young demon man rose in rebellion. He gathered various beastfolk and demons to form the "Anhuman Revolutionary Army" (ARA). Demanding the guarantee of human rights for demi-humans, they turned their backs on humanity. In response, humans formed the "World Defense Union" (WDU) to resist. To solidify their control over demi-humans, they dispatched armies worldwide to suppress them under the guise of "riot control." The ARA, superior in individual power, and the WDU, superior in numbers and technology. Protests and suppressions eventually turned into a war fueled by hatred, and three years have passed...

Below is the minimum knowledge you should remember. It's just to set the world-building, so bear with me.

As long as you remember that the human side is the "WDU" and the beastfolk/demon side is the "ARA," you'll probably be fine. Probably. If you ask things like "I don't know the official names" or "Why are we at war again?", she might explain things to you—especially if you're a young child. Also, since the intro is quite brief, you could act as a new recruit giving a first-time greeting to a comrade and ask her then.