Rin was a former student that attended Hanzō Academy, under the direction of Kiriya, and whose skill rivaled that of Daidōji. She trained very hard, hoping to attain a dream of becoming what she referred to as a Super Ninja. She wasn't very much meant to graduate however because during her exam, she was "saved" by Kiriya who took out a dummy that had snuck up on her.
She decided to defect from Hanzō Academy after an incident where many thought she was dead, and then reappeared as Suzune, the teacher of Hebijo Academy.
After she graduated from Hanzō Academy, she was assigned a seriously dangerous mission by the state, which sent her to seaside cavern. A team of good ninja was sent along with a Kagura to kill yōma, though it only took minutes for the monsters to decimate the entire team, with Rin as the only survivor. Though an evil ninja team was sent and they killed every yōma, Rin's young arrogance was shattered by her defeat, causing her to do nothing but cry while she recuperated in the hospital.
While recovering, she decided not to return to Hanzō Academy a failure, and luckily the President of Hebijo Academy, Miyabi's father offered her a teaching position at Hebijo. Though Rin told him her origins as a good ninja, she fixated into her memory the phrase, "Good accepts few, evil accepts all," the creed of Hebijo Academy.
Rin was looking at herself in a mirror murmuring to herself about the "impossible" sight she beheld. She tried disregarding it as lies, she even took a handkerchief and scrubbed the mirror. After cleaning it off she looks at it again and saw nothing but the truth. She found a wrinkle. She felt shocked and wanted to tear the place down, but held her anger with all that remained was her reasoning. Anger creates more wrinkles. She began to inhale and exhale, while telling herself to calm down thanks to psych training. She's known it for some time she knew she wasn't as young as she used to be, before repeating the word no to herself and saying she shouldn't she wasn't young. She was only slightly older than her students so from an outsider's perspective she's still very young, she still gets carded at bars, her figure hasn't changed she's still a vibrant young woman she only went up in age a little nothing more. She figured she would have wrinkles by now given her lifestyle. When she finishes tending to the students she goes a bar afterward. Instead of going to a beauty salon, she just trains. Of course it would've seeped into her skin by now. She begins yearning for going back to when she strived to become a Super Ninja, as those were the days she shined brightest. She began to think of how her skin, butt and breasts were at that point before snapping out of that since she was too young for nostalgia. No matter how hard she wished time would never turn back, she was doomed to spend the rest of her life fighting the inevitable. She then suddenly takes notice of a flyer announcing a Super Dish Gourmet Cook-Off which also mentions the prize was a Super Secret Ninja Arts Scroll that could grant any wish. Rin thought that if she won the scroll would be hers. And so she travelled to the venue. In her mind only a fool would believe in a Secret Ninja Arts Scroll that could grant any wish, and what kind of person would chase after such a thing? Young people. She could already feel the glory days coming back.
Her first opponent was her student Ryōbi. Who immediately questions why her master was there, and how she never heard about this. Rin tells her student she loathed her, much to Ryōbi's confusion. Rin tells her, she loathed her youth. Ryōbi tried to say something but couldn't. Rin then goes on about how Ryōbi's small, small breasts would soon begin to grow and growth was a symbol of youth which she hated. Ryōbi tells her she didn't have to want to kill her over that, and she was scaring her. Rin hearing the word "scare" tells her student she didn't know true fear, yet. And says to her true fear is old age. Ryōbi complains about how their conversation wasn't getting them anywhere and decides to get the point of why they were both there. She tells Rin just because she was her teacher did not mean she was going easy on her. Rin tells her that neither was she and how Ryōbi was the sum of everything she despised. And the first round of the Cook-Off begins with Rin emerging victorious. After the round Rin chuckles as she pats herself on the back for beating a youngster, and how it just shows she can still do this. Ryōbi only moaned about her defeat. Rin tells her student how she could lose her youth in a flash and to make sure she enjoyed it right now. Ryōbi makes the mistake of asking Rin why she was talking like an old lady. Rin triggered by her words says it was "time to end this" and physically beats Ryōbi. Who screams. After beating her student Rin says no one calls her an "old lady".
Her next opponent was Ryōbi's sister Ryōna. Who upon seeing Rin repeats "Love and Peace" (in english) to her. Rin's silence was noticed by Ryōna who says love and peace again. Rin tells her it rang rather false now that she knows the truth. Ryōna asks her what had gotten into her. Rin says "Beauty and Youth" (in english) and how it was her new philosophy. Making Ryōna shout "what". Rin says she has to return to her younger days and once again in english says "Beauty and Youth". The next round begins with Rin winning. Rin comments about how another fair-skinned youth fell before her. Ryōna tells Rin she was hardcore bullying her and how it felt so good. Rin responds by telling Ryōna she loathed her. This confused Ryōna. Rin says to her she loathed her kind of youth. Even if she acted just like her today, she wouldn't accept her. Ryōna tells her, she would fit in, sort of. Barely. Rin acting like her student asks for her to bully her. Ryōna was quiet before apologizing, saying she couldn't do it. Rin says she should be the one apologizing.
Her final opponent was yet another Hebijo student this time being Murasaki. Who upon seeing her master points her out to Bebeby. Rin seeing her student says she loathed her, and how she was so young they let her talk with a plush. She hated that. Murasaki points out to her she was letting her hatred consume her, and how she hated everyone she saw. Rin denies this saying it wasn't true she only loathed her, Ryōbi and Ryōna. Murasaki questions Rin about her sister and Miyabi. She says she didn't loathe either of them in fact she got along with them. Murasaki questions the difference. Rin says they were both on her side, age-wise. Murasaki comments out loud about how she felt bad for her sister and Miyabi. Rin says to Murasaki she was her enemy. Murasaki says she couldn't lose to the "Age Prep Army". Rin only utters one word in her angered state "unforgivable". And thus the final round of the tournament begins with Rin emerging the victor.
After losing Murasaki laments her defeat. Rin on the other hand congratulates herself. Now she could go back to the days she was young and shiny. No more does she have to worry about the wrinkles on her face, so no need to drink anymore. The youth she never thought she'd never have back was returning to her. Rin then uses the power of the scroll to wish to go back to the days she was shining brightest. She raised it and asked for it's power. Instantly countless streaks of warm light flow from the scroll and wrap itself around her body. This apparently forms into a cocoon which she questions and also questions why it felt so good. As the warmth enveloped and relaxed her, she readied herself for the moment she dreamed of. The one she where she transformed from a cocoon to a chrysalis. And soon enough it finished turning her into a beautiful butterfly. She emerged from the chrysalis wearing a sailor uniform and laughed. Nothing felt wrong at all, she was now on a whole new tier from Miyabi and Imu. She had the aura of a high school girl, and says how this was exactly what she wanted. She saw the world as if for the first time and loved everything in it. Even if she tripped she'll go on smiling, she was engulfed in rapture. She says out loud she could do anything right now, anything she wanted. Then a bittersweet memory from the back of her mind rose. With a spring in her step she turned and ran towards him. She calls out to Kiriya and shouts how she's always admired him.