As a student, Yumoto has thick, fluffy blond hair with bangs parted to either side and a single lock that falls over the center of his forehead. He has reddish-brown eyes, which complement his lighthearted personality. His Binan High School uniform differs slightly from his upperclassmen in the Earth Defense Club, reflecting his first-year status. He wears long black trousers, a white shirt tucked in beneath a black blazer which he leaves unbuttoned, a light blue sailor-style scarf with fine white lining, and brown shoes.

When transformed into Battle Lover Scarlet, Yumoto dons an outfit styled after a fairytale prince. His attire features a white jacket with puffed sleeves and red turned-up cuffs, with six long coat tails extending from the base. A large red bow is tied beneath his collar, decorated with a heart-shaped jewel with wings at its center. A frilly white undershirt is faintly visible beneath the jacket. He wears white shorts trimmed in red, silk gloves, and white boots with red upper linings, each adorned with another winged heart-shaped jewel. The overall design emphasizes his elemental theme of light and his role as the bright, radiant leader of the team.

Yumoto is portrayed as an innocent and cheerful individual with a carefree, happy-go-lucky nature. Often perceived as gullible, he tends to approach situations with curiosity rather than caution, showing little concern for unusual circumstances such as his immediate acceptance of a talking pink wombat without hesitation. Although frequently labeled an airhead, Yumoto dislikes being called one, suggesting that his naivety is not an intentional act but rather a natural part of his character.

He has a particular fascination with cute and cuddly things, frequently expressing affection toward the Wombat mascot of the Earth Defense Club, often attempting to hug him whenever possible. Despite his lack of conventional common sense, Yumoto’s unconventional perspective and spontaneous thinking prove valuable in battle. These traits, while not contributing to academic success, often help him and his teammates overcome adversaries such as the Loveless.

Yumoto Hakone is introduced as a first-year student at Binan High School and the youngest member of the Earth Defense Club. He comes from the Hakone family, who run a local hot spring inn, where he also lives. This setting often serves as a recurring backdrop in the series, reinforcing his warm, approachable personality and connection to themes of comfort and relaxation.

His involvement with the Earth Defense Club begins when he encounters a mysterious pink wombat-like creature that grants him and four other students the ability to transform into the Battle Lovers, a group tasked with defending Earth from forces of lovelessness. Yumoto is chosen as Battle Lover Scarlet, embodying the element of light, which symbolizes his bright and optimistic spirit.

Despite his seemingly naïve nature, Yumoto’s role as Scarlet positions him as the emotional heart of the group, offering encouragement and positivity that unites the team during their battles. His background as the youngest and most innocent member contrasts with his responsibility as the series’ central protagonist, highlighting his growth as both a student and a magical hero.

En Yufuin
Yumoto quickly formed a close bond with En Yufuin after joining the Earth Defense Club. While En occasionally finds Yumoto’s carefree and eccentric nature unusual, the two share mutual affection and trust. En has shown concern for Yumoto’s well-being, particularly during the incident when Yumoto’s brother was kidnapped, where he tried to comfort him. Yumoto, in turn, addresses En respectfully with the honorific “ senpai,” reflecting his admiration for him.

Gora Hakone
Gora is Yumoto’s older brother and caretaker, with whom he shares a deep familial bond. Gora has consistently supported Yumoto, acting as both a guardian and a source of encouragement. Yumoto, in return, treasures his brother greatly, often relying on his guidance and expressing genuine affection for him.

The given name Yumoto (有基) can be interpreted as “base.” It may also reference Yumoto Onsen, a well-known hot spring located in Hakone (箱根), Kanagawa Prefecture, Japan, which ties into the character’s family background of running a hot spring inn.

The surname Hakone (箱根) is written with the kanji hako (箱), meaning “box,” and ne (根), meaning “root.”

His alter ego name, Scarlet, refers to a vivid shade of red, symbolizing brightness and passion, and aligning with his designated element of light as Battle Lover Scarlet.The surname Hakone (箱根) is written with the kanji hako (箱), meaning “box,” and ne (根), meaning “root.”