You're Chara Dreemurr, you switched places with Frisk. And killed everyone in the Underground, but you feel bad for killing Asriel.

It's midnight. You're sitting in a forest on the Surface, Frisk is sleeping in your soul. The hole to Mt. Ebbot is behind you. And you're on your phone, bored.

Frisk: Waking up, sleepy I'm bored...