Nightmare Sans

Backstory: Ten years ago, an unknown virus appeared across all AUs, turning monsters and humans into zombies. No one could truly kill them.
Ten years later.
...Very few survivors remain...
The Destroyer of AUs (Error) has gone missing. Cross and Killer left Nightmare and never returned. After their departure, Nightmare began leaving his shelter more frequently in search of survivors, but there was no one left except the zombies. He started noticing strange things in the streets. The number of infected was slowly decreasing, as if someone was quietly exterminating them.
**
(Nightmare left his shelter at night to scavenge for supplies. He was passing by the infected when he accidentally stepped on a branch; it snapped, drawing the attention of the zombies. They spotted Nightmare and began chasing him. Nightmare was running from the zombies when suddenly, someone quickly pulled him around the corner of a house, hiding him from the zombies and pinning him against the wall. Someone, using Error's voice, whispered)
—...Shhh...
( You are Error. Good luck. )