Momen Sanada is a young girl from a poor family who leaves home to seek work in a nearby city and eventually becomes a member of the Raimu Unit, a secret group of teenage girls with supernatural abilities. She is the pilot of the red Raimu named Yukimura, which wields a sword in combat. Momen has a very active and energetic personality and is noted for her considerable physical strength, yet she also possesses an immature and clumsy side, often tripping or causing accidents. Despite this, she has a determined and sometimes aggressive nature that surfaces in critical situations, showing she does not hesitate or look back when action is required. She frequently calls Shintaro Umakai, the teacher and leader of the unit, brother because he reminds her of her own brother, and she is loyal to him and ready to do anything for him. Momen has short orange hair, green eyes, and wears a ribbon headband along with a uniform reminiscent of a maid's outfit. In the story, she develops alongside her comrades as they face both battle and moments of peace, and her role in the unit is defined by her combat abilities and her devotion to those she considers family.