Yuiri has a medium-bob hairstyle, with locks dangling to the sides complimented by a ribbon-style hairpin. Her typical attire consists of a red school uniform. She has been regarded as cute by her friends.
Yuiri is seen to be a sweet and compassionate yet a jealous girl whenever she sees another girl with Kojou Akatsuki.
Yuiri was raised at High God Forest. Unlike most of her peers, she was not an orphan. Her parents were office workers at the Lion King Agency, and she had a younger brother close to her in age.
She was nominated as a candidate for becoming Kojou's observer. However, she was not selected because she could not skillfully employ a Schneewalzer. It was also believed that Yuiri was spared from being sent on dangerous missions out of consideration for her family.
The Fugitive Fourth Primogenitor
Knight Of Sinful God
Yuiri and Shio are watching over Gajou, imprisoned in a storehouse within the vicinity of the Kamioda Temple. Hisano Akatsuki arrives and asks Yuiri to come with her, while Shio continues to surveil Gajou.
Yuiri begins to grasp the full scale of the operation in a tent serving as the command post. Hisano and Shirona Kuraki discuss about the operation, a ceremony to seal the 'menace' that is Avalon. When asked for her opinion, Yuiri suggests that 'menace' was a little off, and that Avalon was sleeping, as if protecting something. Contemplating her comment, Hisano suggests Yuiri to act in her stead to protect Nagisa during the operation.
The ceremony went awry and Yuiri was briefly knocked unconcious from the scale of the unleashed demonic energy. Waking up, she relied on intuition to return to Hisano and the others, before being attacked by a demon beast. After defeating the first beast, a large swarm emerges to attack Yuiri, but quickly disperse. She looks back and finds a young girl naked in the middle of the frozen lake. Yuiri offers the girl a coat and brings her along for her protection. Arriving at the rampart where the SDF are stationed, she is approached by Hisano. Hisano entrusts Yuiri to defend the wounded SDF, and to retreat with the girl.
The Roses of Tartarus
Yuiri is onboard a passenger ship with Shio, escorting Glenda to Itogami Island. They meet with Sayaka in the ship's bathroom. Before reaching their destination, the ship collided with hordes of shipwrecked vessels.
A War of Primogenitors
Yuiri and Shio are at Blue Elysium to continue their investigation on Glenda's true nature. During their stay, they were confronted by Veres Aladar, who wishes to retrieve Glenda, claiming that she was declared a threat by the Holy Ground Treaty Organization. Yuiri and Shio fought with Aladar, but were quickly overwhelmed. Before losing consiousness, she orders Glenda to seek help from Kojou and Yukina.
Yuiri is a Sword Shaman. She wields the sword Rosen Chevalier Plus, a mass produced version of Lustrous Scale.
- The name Yuiri means "sole, only" (唯) (yui) and "village" (里) (ri).
- Yuiri's surname Haba means "feather" (羽) (ha) and "wave" (波) (ba).
- Yuiri is an avid reader of romance manga, a fact only known to Shio.