|Nickname/s||Jolly Roger (lit. Death Sentence)|
|Voice Actor||Izumi Kitta|
Yuuri Oreki is a teacher from Hagun Academy and the homeroom teacher from Ikki's class. She is known by the nickname "Jolly Roger" (死の宣告, Shi no Senkoku, lit., "Death Sentence").
Yuuri is a young beautiful woman, although she does look sick most of the time due to her weak constitution and vomiting most of the time. She has long dark hair, with bangs that cover her forehead, as well as covering her ears completely, it is also long enough that it goes down to her back. She is usually seen wearing a long sleeved white blouse, as well as a long dark skirt, and high heels.
Yuuri is a kind hearted woman who cares for all her students, going as far as to fake a child and hyper-like personality to reduce the tension of the first year students. She also constantly encourages her students to have faith in themselves.
Yuuri is known to have a weak constitution, vomiting one liter of blood a day since childhood.
A year before the story, Yuuri worked as an examiner during the entrance examinations of Hagun Academy. One of the new people trying to enter was Ikki Kurogane, who Yuuri initially dismissed due to his low mana capacity. Ikki, however, challenged Yuuri to a battle to prove his worth, which Yuuri accepted. During their battle, Ikki showcased his Blade Steal, copying Yuuri's own swordsmanship and using it against her, which highly impressed Yuuri. As their battle continued, Ikki was eventually forced to utilize his Noble Art, Ittou Shura, to overcome the effects of Yuuri's own Noble Art, Violet Pain. Ikki eventually wins the battle, by using a martial arts technique to snatch away Yuuri's weapon and deliver the finishing blow. Because of this, Ikki was accepted into Hagun by Yuuri, who took a liking to him.
New Term, Reunion and Rebellion Edit
Yuuri welcomed her new students on their first day, explaining the new rules of the school set up by the new director, Kurono Shinguuji, for the upcoming Seven Stars Sword Art Festival and encouraging her students to take part in the selection battles for the Festival, seeing it as a chance for even the weaker students to shine. The homeroom then ended abruptly as Yuuri starts vomiting blood, as she was taken to the infirmary by Ikki.
Debut Battle and Vow Edit
Impossible Victory, Decisive Battle, and New Beginnings Edit
Yuuri is then seen finding a broken building, and a sorrowful Ikki. He tells her what had happened to the building, and with Ayase, stating that Ayase will probably cheat in their match. Yuuri offers to keep a close eye on Ayase, but Ikki tells her that he doesn't want Yuuri to call out Ayase, as he wants to help her not beat her. Yuuri agrees and does not say anything while she commentates on the match believing in her student Ikki.
Siege, Reunion and Trap Edit
Yuuri serves as the observer and judge for Ikki's 18th and 19th selection battle matches while he was detained inside the Japan branch headquarters, noticing that Ikki's sickness is too unnatural. Yuuri is later seen among one of the supporters for Ikki during his match against Tohka Todo, encouraging him.
Akatsuki Strikes Edit
Yuuri was sweeping at Hagun Academy when Ayase approached her and thanked her for looking the other way during her and Ikki's match. Yuuri, however, corrected her in saying it was all thanks to Ikki for that. Yuuri and Ayase's conversation is then interrupted by incoming members of Akatsuki one of which tries to attack Ayase. Ayase, however, is protected by Yuuri who planned to knock out the students first and ask question later. Yuuri is, however, defeated by the attacker after the attacker used the ability Total Reflect. They are both later found by Ikki and Stella knocked out by a destroyed Hagun Academy.
Pain Sharing: Yuuri has the ability to share the pain she feels with all enemies within range. At max, it covers many kilometers. It's a strategic-class ability that can strike several hundreds of people simultaneously.
Expert Swordsmanship: Yuuri is skilled in swordsmanship, being able to clash with Ikki, an absolutely formidable swordsman himself.
Immense Endurance: Yuuri's endurance is spectacular, being able to act normally despite being in constant pain. Due to having experienced pain from childhood, Yuuri has gained great endurance to it, being able to even cut herself without any hesitation.
Unnamed Cutlass Device: Yuuri's Device takes the form of a blood-red cutlass.
- Violet Pain (血染めの海原, Chizome no Umihara, lit. "Blood Staining Ocean"): Yuuri's Noble Art that shares her pain with other people. As she is constantly sick, this ability is especially useful. It can affect multiple people even many kilometers away.
- Due to her sickness, Yuuri is very knowledgeable in medicine. She though does have a habit of eating her pills like candies.