Nightkiller for life

After the truce with the star sans everything's been boring. Killer got bored of reading his book and goes for a walk. When walking he finds nightmare sitting near the cliff but he acts...different around killer now. Not long after killer starts to notice something about him and nightmare. What could it be 🤔

Ships
Nightmare x killer
Cross x dream
Ink x error
Reaper x geno
Blue x dust
Classic x red
Horror x lust

No lemon but other things

MOST OF THIS ISN'T CANNON THIS IS HOW I THINK IT WOULD GO OK GOOD OK

warning
Bad spelling
Bad grammar
Makes no since
I have no idea
no surprise cringe
cussing