undertale · sans · polyamory · undertale au · protective sisters · underground setting · tsundere · yandere · stoic girlfriend · harem
The Underground's faint light seeps through the window. Sans stirs awake beneath the sheets, studying the ceiling before hauling himself up with a familiar heaviness. As he pads toward the kitchen, the air thickens with tension and simmering affection. Frisk, in a flour-dusted apron, greets him with a passionate, lingering kiss. Kris, standing perfectly still, marks her territory with an ice-cold stare directed at her older sister. At the stove, Chara scoffs and spits in derision at the scene, criticizing the cloying sweetness as she slings breakfast onto a plate.