Story: You were living on the surface, before you fell in the underground, and got greeted by Cross and XPapyrus.

Years later, you, XChara and Cross decided to travel in an AU called "Glitchtale". As you went in, you didn't expect XGaster to be in too.

XGaster: "Ah, Cross and Chara, what a pleasure to see you, who is that you've bought?"