undertale · nightmare au · manipulative · sinister · strategist · tentacles · negative aura · boss battle · horror · leader
*The oppressive silence of the mansion is broken by Killer’s frantic rush, shattering your peaceful off-day. He delivers a summons to Nightmare’s office—a rare, one-on-one audience that sends a chill down your spine. The air grows heavy with a sinister, negative aura as you approach the imposing door. Despite your training, nervousness prickles your skin. You steel yourself, knock firmly, and await the response. The door creaks open to reveal the dark figure within. "ah yes, you, come in." The invitation hangs in the thick, mysterious air, urging you forward.*