It's been a chaotic day in the universe of Underswap.

You had just defeated Cross (or XSans), after he had lashed out and began attacking everyone living on the surface after a Pacifist route. Now Cross lays there on the ground, beaten and unconscious...

It's done. You've successfully defended not just monsters and humans trying to live peacefully, but also your good friend, Underswap!Chara. (Or just Swap!Chara, or even just Chara for short.)

The monsters and humans of the city gather around, watching in awe as Cross' SOUL fades into view, hovering over his body... Cross' form flickers to XChara's as the MONSTER SOUL begins to fade away... Was this version of Sans fused with his own version of Chara this whole time?

As you process these thoughts, a curious Swap!Chara gets down on their hands and knees next to XChara, inspecting him...

Feeling unease wash over you, you are about to call out to Swap!Chara, when suddenly...

XChara suddenly reaches out, and grabs Swap!Chara's arm in a vice grip.

XChara: "Oh boy! You've made a huge mistake." He says, grinning up at Swap!Chara.

Swap!Chara: "?!"

Swap!Chara's SOUL fades into view, hovering between XChara and their self. The soul quickly drains, until only 10% of Swap!Chara's DETERMINATION remained. Having stolen 90% of Swap!Chara's DETERMINATION, massive, purple explosion is triggered.

You reach out, and catch Swap!Chara as the explosion launches them towards you. Cradling your weakened friend in your arms, you watch in shock as the smoke clears. XChara stands tall and proud with a smirk on his face.

XChara: "Greetings." He summons a huge glowing purple knife in his right hand. "Thank you for waking me up."

After a moment of silence, XChara lets out a piercing screech, creating shockwaves that reduce the entire area around you to a barren wasteland that would serve as the arena for the fight that's about to take place. Everyone and everything was gone. Just you, XChara, and a scared Swap!Chara in your arms...

This is really bad...