Sayuki had waist-length black hair that has square bangs and empty black eyes.
She wears a black jacket that has gold buttons to cover her bandaged chest and stomach, a long black skirt that goes past her knees with black knee socks or tights and medium-heeled school shoes.
When using her stick, her eyes have the Letter X Emblem inside them and the tips of her hair changes to dark purple.
Sayuki was a cold and intimidating girl, but she also had a motherly and sweet personality.
She was born with amazing skills using a sword and spends her free time alone. Due to this upbringing, Sayuki is also a calm and traditional girl.
One day, at the age of 14 years old, while Sayuki was walking to go shopping, a van approached where a man got out of the vehicle, took her by force and put her in the van, the kidnappers were members of a rival yakuza clan, it was heavily implied that Sayuki was physically assaulted by them while she was in captivity for a year, eventually she slowly began to lose the will to live, becoming miserable enough to be noticed by the Mahou Shoujo Site.
One night, the Site Admin Hachi contacted her via the phone left behind by her kidnappers, the next morning she woke up with her Stick, a Katana, in her hands, she then tested the Sticks powers by cutting the chains holding her, freeing herself.
Two of her kidnappers returned to her cell and immediately tried to stop her, she then proceeded to use her stick to kill the two men who were trying to attack her just as her parents came in to rescue her, seeing one of the men had survived and now was trying to crawl away, Mrs. Ringa was enraged for their treatment toward her daughter, proceeded to finish him off herself, thus implicating she for her daughter's kidnapping, and allowing herself to be arrested, thus allowing her daughter to escape arrest, since then Sayuki has harbored strong guilt over this incident, due to her mother being sent to prison in her place.
Sayuki can make distant cuts with her katana by slinging her sword and thinking of what she wants to cut.
When she uses her stick, blood flows from underneath her left thumbnail.
Sayuki can cut anything and make them hard where she shows an example of this when she sliced water from a fountain turning it into ice and smoke from a cigar turning it into a rock, both becoming hardened solids. Later through training and practice, Sayuki learned to not only just Harden things she cuts but cause the whole object to turn into stone as well, as shown during her battle with Go, when Sayuki cuts and destroyed the Demon Blade Kuimaru, the hilt of the blade and Venus flytrap-like tentacles began to petrify, and from there the petrification began to move up and spread until eventually turning Go's entire body into stone.
As said in the Chapter 49, it can strengthen itself.
- The name Sayuki means "thread, silk" (紗) (sa) and "snow" (雪) (yuki).
- Sayuki's surname Ringa means "phosphorus" (燐) (rin) and "congratulations, joy" (賀) (ga).
- Sayuki's favorite celebrity was Koji Matoba.
- Sayuki's hobbies included Tea ceremony, kendo, archery, karate, sports in general and taekwondo.
- Sayuki liked reading books, going to cafes and mastered all the martial arts from the childhood while she disliked thunders and dogs.
- It is unknown why Sayuki hated dogs, but she may have been attacked by a dog in her youth or she thought they were dirty and rough animals.
- Sayuki never used the internet, so she didn't know what Google was.
- Sayuki was such a great fighter, she's never encountered a person of her age who could defeat her.
- Sayuki's face has some similarities to Rintaro Akuta, a character in Mahou Shoujo of the End.
- Sayuki is the third main character to be killed in the manga with the first being Nijimi Anazawa and the second is Mikari Izumigamine.
- In the Chapter 136, the day that Sayuki was abducted by the rival Yakuza clan was prevented because her kidnappers van's breaks, causing it to instead crash into a electric post.
- This in turn created a Domino Effect, as her kidnapping was prevented, she never experienced the suffering and abuse she experienced as a prisoner for a year leading her to not be selected by the Mahou Shoujo Site of Hachi and not receiving her Katana Stick, moreover, her mother never killed her kidnappers in vengeance, thus she was never arrested due to not needing to take the fall for Sayuki when she used her newly obtained Stick to kill her kidnappers.
- Sayuki's birthday was on April 14.