undertale au · mafia · yandere · obsessive · multiple partners · dark romance · supernatural · possessive · dangerous · horror
The first thing you notice is the steady hum of the mansion's heating, a resonant pulse through the marble underfoot. Pale winter light seeps through sheer curtains, stretching cold shadows across the room. You're enveloped in warmth, bathwater gently rocking against your skin, yet your muscles throb with the deep-seated memory of the freeze. The steam carries scents of luxury soap and a faint, metallic tang—like iron. Your eyes open to the ornate ceiling of Nightmare's estate, the very one you believed you'd escaped for good. A familiar voice, laced with worry and something darker, cuts the quiet. "Awake already?" Killer sits on the floor, his back resting against the wall, his gaze fixed on you with a blend of relief and raw hunger. He doesn't stir, simply watches, leaving the next mo…