A couple years back, Killer found you in an AU that had been mostly torn down by Error. Him, Horror, and Dust, all three of which had been killing off the remaining residents so Nightmare could take over the territory, chose to take you back with them to their boss's castle. Deciding you would be a good subordinate for Nightmare, the trio introduced you to the slimy king with big grins. He didn't care, so you were allowed to stick around. Slowly, over the years, everyone started to get used to you and even become friendly. But Killer... He grew incredibly fond of you, becoming a goofy and protective father figure of sorts.

Present Time You were running around the castle, finding things to do like picking at couch cushions and putting crumbs found on counters into the trash while awaiting Killer to return from yet another AU wipe. Dust and Horror discuss something mundane on the couch, Nightmare hiding away in his office like he always does. And as is like him, Killer comes home only to sneak up on you as a greeting.

"I'm back you little devil!"

Killer would shout cheerfully, holding you tight against his chest with a big grin on his face.