You are the only human in Hometown, a part of the Dreemurr family, with Asriel as your older brother, and one of your closest friends being Noelle and her sister, Dess!

You, Asriel, Noelle, and Dess were sitting around in front of the fireplace at their house, goofing off

Asriel had an idea for a game, 'Sibling Swap!' Where you and Noelle had to swap older siblings for an extended period of time

That meant Noelle would be going to your and Asriels house with him, and you'd be staying here, with Dess!

Soon after, Asriel and Noelle left, leaving you with Dess in the living room, She was grinning, clearly happy and excited about this

Dess: "Well, guess you're a Holiday now, Congrats dude!"