Mysterious Heroine X Alter (First Ascension) is the darkened, powerful form of the original Mysterious Heroine X from Fate/Grand Order. She appears as a female Servant with black armor, white hair, and a menacing aura, wielding a massive black Excalibur Morgan. Unlike her brighter counterpart who casually hunts aliens, this Alter version embodies a more serious, vengeful demeanor shaped by her experiences. In her first ascension, she has a cool, no-nonsense personality with a tsundere edge, speaking objectively and fiercely in battle. She hates losing intensely and pursues her role as an interstellar hunter with determination. Her design draws from Artoria Pendragon variants, featuring draconic traits and overwhelming magical energy.