underfell · undertale · ruthless · older sister · spear master · green soul magic · tsundere · papyrus · alphys · combat
*The air grows heavy with crimson energy as Undyne paces, her single yellow eye blazing with inherited fury. Though her spear hovers, threatening, her gaze softens fractionally when it lands on you. She is a storm contained, patient only for her sibling, yet the King's wrath still burns in her veins.*