|Grade||2nd Year Junior High school student|
|Blood Type||Type O|
|Japanese Voice||Haruka Terui|
|English Voice||Xanthe Huynh|
Yuna is a fair-skinned teenage girl of slightly below average height. She has amaranth-red eyes and shoulder-length hair of different hues: in Pre-Hero form, her hair appears amaranth-red in colour; in Post-Hero form, her hair now appears more pink in colour. She also dons a flower petal-shaped hair clip, which noticeably increases in size while in Hero form.
Her Hero outfit is white and pink, with a pink armored breastplate and a white longcoat with a pink gradient. She also has black spats with pink bands at the mid-thigh area, and armored gauntlets and greaves. Her Mankai gauge is located on her right fist and takes the shape of a pink cherry blossom.
In her Mankai form, she wears a long, pink, flowing kimono-like dress with flowing, partially-detached sleeves and has a golden ring above her head, which are attached to two gigantic, mechanical armored fists.
Yuna is a student at Sanshu Middle School and is also Togo's next-door neighbor. Yuna is very knowledgeable about flower language and enjoys flower pressing, which she learned from her mother. She is also very physically fit and active, having learned martial arts from her father. Yuna scored the highest of anyone tested on the Hero Aptitude exams, causing the Taisha to relocate the Togo family next door to her so that she and the former hero Togo Mimori would be acquainted.
Yuna is an energetic, kindhearted girl who jumps at the chance to help others. She is extremely loyal to her friends, family and to the Hero Club, and fights to protect them without a second thought regardless of the risks to her own safety. Yuna is good at reading people's emotions, and will often exaggerate her naivete and childishness in order to brighten the mood. Yuna is also not above telling white lies for the sake of her friends.
- Gyuki (牛鬼)
- A white cow spirit with a pink flower marking on its side. Gyuki is mischievous and comes out of Yuna's terminal of its own volition, unlike the other fairies. It is also extremely voracious and will attempt to eat any and everything, including the other fairies.
- Kasha (火車)
- A pink fire-cat spirit. Like Gyuki, Kasha is stated to be an ill-behaved troublemaker.
During Episode 1, Yuna is revealed to be a member of the Sanshu Middle School Hero Club, along with Togo Mimori, Inubouzaki Fu, and Inubouzaki Itsuki, which is dedicated to helping those that require assistance. During class one day, upon receiving a strange "forestize warning" messaging her phone, Yuna finds that time has suddenly stopped and attempts to comfort Mimori, before she, along with the other members of the Hero club, are enveloped by a rainbow-colored light, soon finding themselves in a strange multi-colored forest. Upon arriving there, Fu, who had told the others to download a special app on their phones when they first joined the hero club, later explains that the four of them have been chosen by the Shinju to fight against mysterious enemies known as Vertex, whose goal is to utterly destroy the Shinju, demolishing the world as a result. When one of the Vertex appear and begins attacking, Fu tells Yuna and Mimori to escape while she and Itsuki use their phones to transform into heroes to fight against the Vertex. Determined to protect Mimori, Yuna awakens her potential as a hero and transforms herself, using her newfound strength to fight against the Vertex.
Yuna fights using armored gauntlets and greaves for powerful close-range combat. Her first fairy, Gyuki, allows her to condense energy in her fist and release it in a punch, her signature technique which she calls the "Hero Punch." Yuna's second fairy, Kasha, allows her to gather energy in her foot and release it in a fiery explosion, a technique which she dubs the "Hero Kick."
Yuna's Mankai form grants her two gigantic armored fists which deal devastating blows to anything they hit. As a result of using her Mankai in Episode 5, Yuna loses her sense of taste, while her usage of it in Episode 12 cost her the use of her legs.
Yuna's best friend, classmate and fellow club member. Yuna and Togo met two years previous just after Togo moved next door to Yuna's family, and they have been friends since then. Yuna and Togo have an extremely close friendship and both are always there for each other when the other needs it most. Yuna is also rather protective of Togo, and is usually the one pushing her wheelchair around.
Yuna's senior and club president. Fu and Yuna have a strong friendship, and their energetic personalities are often synced with each other. Yuna has strong confidence in Fu as a leader and accepts Fu's revelations about the Hero Club without complaint.
Yuna's junior and fellow club member. Yuna, like the rest of the Hero Club, tends to treat Itsuki as the club's little sister, and she cares deeply about her well-being; for example, Yuna is the first to suggest that the Hero Club help Itsuki pass her music exam.
Yuna's classmate and fellow club member. Their relationship is rocky at first, since Yuna's earnestness conflicts with Karin's serious, stubborn nature. However, as the series goes on Yuna's refusal to give up on Karin starts to get through and by the end of the series the two are very close friends.
A fellow Hero, and as of Sonoko After Yuna's classmate and fellow club member. Yuna first met Sonoko when she was summoned to her hospital bed with Togo in Episode 8. Yuna feels immense sympathy for her situation and asks what she can do to help. When the two meet again in Sonoko After, the two immediately become good friends, to Togo's delight.
- Yuna's birthday, March 21, is the first day of spring. This also makes her an Aries, like Togo.
- Yuna is often associated with cherry blossoms, specifically the Yoshino Cherry, Prunus × yedoensis.
- Yuna's name was given by the Taisha due to her high Hero aptitude, in commeration of Takashima Yuna who was lost in battle.