Before the tragic loss of her parents (Kurōdo and Iyu) to Horrors, Yuna had a happy childhood. Training in both the ways of a Makai Knight and Priestess, Yuna looked up to her father and wanted to become a knight like him. Unfortunately, Yuna was orphaned after White Horror Ring took them both away from her. However, Yuna recovered her father's severed right arm and Makai Blade. Unable to find peace with her father's death, Makai Priest Kain (Kurōdo's partner) helped fuse Kurōdo's ulna bone to her right forearm to help her wield her dad's sword. Although she can't summon her father's armor, she teamed up with Kain in hopes to slay Ring for her parents.
Motivated by vengeance and neither a fully developed swordswoman nor priestess, Yuna is aided by Kain (due to his guilt over Kurōdo's death) in her quest to slay Ring. In Black Blood, the Makai Order sanctioned this team to take on Ring; Silver Knight Zero was added to the mission to help them succeed. As the trio hunted for Ring, their interactions and fights revealed Yuna's anger and impulsivity is a liability; she also displayed her resolve, tenacity, and determination on the field. To complicate matters, Yuna discovered her mother lives and is helping Ring; Yuna intend to make Iyu atone for her crimes. With the help of Rei and Kain, Yuna was able to reunite with Iyu and she sacrificed herself to Ring for Yuna. Without Iyu's support, Rei was able to slay Ring, giving Yuna a cathartic release from her traumas and hate. With renewed focus, Yuna continues to serve the Makai Order and train in the hopes of mastering control of her father's sword and one day wear his armor.
By Makai Tales, Yuna has shown refinement over her abilities. However, she still experiences doubt due to her inability to master her dad's sword, including Kain. However, a fateful encounter with Leo Fudō (a knight and priest) revealed the Senate recognizes her skills. Leo encouraged her to continue her path after parting Kouga's wisdom of having pride as a knight. With Leo's praise over her abilities and supportive words, she found acceptance and happiness within herself; she continues her path as a would-be knight and priestess.
To Be Added
- Makai Knight Training: Kurōdo was a Makai Knight and trained Yuna as a disciple. It's unclear did he intend to transfer his weapon and title to Yuna, but he was a supportive father and encouraged her to work hard despite knowing there is no such thing as a female knight. While it was unfortunate he died before fully transferring his training to her, she continued to train what she remembered. Mildly skilled in combat, Yuna struggles to take down a single Horror and often relies on help to get the job done. Oddly, she never sought out a master to help her complete her training.
- Makai Priestess Training: Iyu trained Yuna in offensive magical casting. Combining her martial arts and sword, Yuna is able to blast destructive bolts at Horrors. A unique ability inherited from Iyu is that she can sing a makai song that has a healing effect on the field. Whenever she sings, her injured party can be healed and rejuvenated to continue fighting. Despite teaming up with Kain, she never ask him nor any other skilled priest (like Rekka or Jabi) to further refine her abilities.
- Makai Blade: Yuna wields her father's sword. After Kurōdo was killed, Yuna wanted to succeed her father as a knight and a means to slay Ring. Without mastery over soul metal, Kain helped her skirt the process by fusing Kurōdo's right ulna bone into Yuna, allowing her to wield his sword. However, this cheat has its limitations. Because Yuna didn't master soul metal the old fashion way, over straining herself can cause a rebound effect on her. This causes Yuna excruciating pain, paralyzing her in combat.
- Madō Brush: Yuna's brush, she uses it to cast charged bolts at her targets in combat. Because of her stronger focus in swordsmanship, she doesn't use magic often.
- Yuna is portrayed by Riria (梨里杏?) who also plays Mio in Ressha Sentai ToQger. As a chlid, she is portrayed by Chiari Komori (小森 茅愛, Komori Chiari).