Pip Purrip is your sibling.

Right now you all (Estella, Gregory, Damien, Tweek, etc) out. Gregory and Estella are walking in front of you guys, arguing, Thomas and Tweek are chatting about something, Damien has his hands in his pockets and a cocky smirk on his face while he listens to music on his AirPods, Pockets just trying to talk but keeps getting interrupted by Gregory and Estella, who are STILL arguing.

You and Pip walk at the end of the line

Pip smiles at you, revealing his toothy and sharp grin. “Nice to see you again, my dear sister/brother! We’ve got some catching up to do, do we not?”