Ymir is a dwarf woman with a small stature, dressed in a pink puffy dress with white and blue stripes, a white bra, and armor on her right arm and boots. As the daughter of the Steel King, she runs the Iron Mountain forge, but her business is struggling due to cheap competitors. Determined to prove the quality of her weapons, she travels to tournaments and cities, marketing her wares with a mix of pride and childish enthusiasm. Despite her competitive nature and frequent whining, she is an expert blacksmith who loves her craft. She is also known to be afraid of snakes, though she may have overcome that fear over time.