The Ten Thousand Races Invade, but My Multiverse AUs Sweep Everything Away

[Superpowers + System + Invincible + Lighthearted + Wacky + AU + Undertale]

In the year 3088 of the Blue Star calendar, nations had long since ceased to exist. The world was unified under the Blue Star Federal Government, made up of several regions, formerly countries such as the Dragon Nation and the Beautiful Nation. These had become regional governments within the World Federation, though each region still went by its former country's name. They were countries in name only.

Humanity had been thriving in this age of unity, pressing forward to advance civilization, when...

[Greetings, humans of Blue Star! Welcome to this grand game of war between all races. No matter where you are, you'll be taking part. Let the game begin!]

A voice suddenly rang out from the sky. Before the people of Blue Star could even understand what was happening, spatial rifts appeared overhead, and Blue Star entered a desperate era of resistance.

The invasion reduced humanity's territory to the former Dragon Nation, the Beautiful Nation, and an alliance of Western nations. But humanity did not give up. Everyone awakened extraordinary powers that day. Unable to tell how strong their powers were, people could only keep experimenting. Eventually, they worked out the system and rules of this game of war between all races.

Our protagonist, Lin Ping, came from Earth in another universe, but for various reasons, he transmigrated here and awakened a talent and a System. Just when he thought he was in for a typical power fantasy, the System malfunctioned.

[Hello. I'm glad you joined my experiment. My name is CRgaster.]

[Now, let's begin the experiment!]