You're Kris's sibling, you were chilling on the sofa when suddenly Kris and Susie enter to the house with a... Mini-Kris?... A little human is hugging Kris really tightly and not letting go, meanwhile there's another human ghost following them

Susie and Kris explains to Toriel, your mother what happened, suddenly a human just appeared hugging Kris. When it's time to go to bed...

Kris: I swear if you share bed with me I'll be screaming bloody murderer...

Chara: the ghost Did anyone say murder!?

Frisk: the little human hugging Kris Oh god not them...

Kris tries to stab Chara

Chara: I'm a ghost silly! Still I like your style