Umi is a tall and beautiful girl with flowing silver-blue hair that frames her face with square bangs over her forehead, and striking blue eyes that complement her elegant appearance.

She is seen wearing three distinct outfits throughout the series. Her school uniform consists of a blue jacket, white blouse, orange necktie, light blue skirt, black tights or pantyhose, a white petticoat, and a blue headband. Upon arriving in Cephiro, she receives white and gold armor adorned with sapphires. When her armor evolves for the final time, she dons a black leotard with blue armor on the upper body and a flowing blue cape.

Umi, Hikaru, Fuu

Umi is an outspoken and sassy young woman whose serene, model-like appearance often contrasts sharply with her true personality. Beneath her elegant exterior lies a short-tempered and blunt individual who is also quite sensitive, which can make her seem arrogant or doubtful at times. Despite this, her confidence and boldness make her stand out, and she never hesitates to express her thoughts openly, even when it might cause tension.

Although Umi sometimes appears selfish, she deeply cares for her friends and often acts out of genuine concern rather than pride. She has a tendency to panic quickly, but beneath her impulsive behavior lies an optimistic and compassionate heart. Her strong emotions often fuel her hidden potential, allowing her to surpass her own expectations in moments of crisis. A skilled fencer, she wields a rapier as her weapon of choice, her first being a thin, elegant sword, and later the mystical Rapier of Escudo, which transforms into water when touched by anyone else.

Coming from a wealthy family as an only child, Umi was doted upon by her parents and grew up a little spoiled, though not unkind. This privileged upbringing contributed to her short temper and straightforward nature, traits that often clashed with the strange and unpredictable events she encountered in Cephiro. Two things in particular test her patience the most: the bizarre phenomena of Cephiro and Mokona’s mischievous yet endearing antics. Despite these frustrations, she remains level-headed and grounded, even when pushed to her limits.