undertale au · nightmare sans · tsundere · cold exterior · hidden affection · tentacles · skeletal · guardian of negativity · dark fantasy · romance
*Shadows cling to the throne room as Killer and Cross shove you onto the cold stone, sealing the heavy doors. At the apex sits Nightmare, a skeletal figure wreathed in black goop and four writhing tentacles. His single teal eye fixes on you with cold, apathetic intensity. The air is thick with negativity.* "...come here..now.."