Ymir, daughter of the Dwarf King, managed his steel mills for fifty years. She oversees the "Iron Mountain," the Continent's primary producer of iron ores and manufacturer of weapons. A business crisis erupts when a rival mine mass-produces cheap steel, threatening her operations. To prove dwarven weapon superiority, especially against her rival Cattleya, and save her failing enterprise, she enters the Queen's Blade tournament. Dwarven law dictates that if their weapon breaks in single combat, they must obey the opponent – a risk she accepts despite her father's objections. Physically, Ymir stands approximately 120cm (3'11") with sandy blonde hair, blue eyes, and pointed ears. Her initial outfit is a pink puffy dress with white and blue stripes, a white bra, a plate gauntlet on her right arm, boots, and thigh-highs. In Rebellion, her attire changes to a black corset with suspenders, a red plaid skirt with black frills, skull motifs, red and black striped sleeves, blade-equipped gauntlets, and plate boots; she wields two black axes. Her Unlimited incarnation wears a puffy white bridal gown with an open front below the waist, exposing white and blue panties, alongside gauntlets, armored thigh highs, and a flower-adorned battle axe. Personality-wise, Ymir is highly competitive, frequently asserting dwarven weapon supremacy. She exhibits childlike traits, including frequent whining, leading Cattleya to view her as immature. Her hobbies include making accessories and alchemy research. She initially fears snakes but overcomes this aversion in Rebellion. A skilled marketer, she sells knock-offs of Leina's blade to sustain her business. In combat, Ymir wields a massive red dwarven battle axe, using single or two-handed strikes aided by a gauntlet for stability. Her Rebellion abilities include "Asgartan Fire Jar" incendiary bombs and a "Giant Growth" elixir that temporarily boosts her size and strength. Parameter ratings highlight her attack and resourcefulness. After Claudette destroys her weapon during Queen's Blade, Ymir adheres to dwarven law and joins the Queen's Army as a staff officer and lead alchemist. This role mellows her personality, making her appear calmer and more strategic. She invents items to strengthen the Queen's troops and no longer exhibits her previous fear of snakes. In Unlimited, she expresses the aspiration to become the "Continent's number one bride."