|Relationship Status||Newly Dating|
Sei Satō is one of the main characters in the yuri series Maria-sama ga Miteru. Also known as Rosa Gigantea. The exact opposite of most of the characters in the series: loud, rough-around-the-edges, she loves doing what she can to push other peoples' buttons. However, Sei is one of the wisest and most caring characters in the series. Though seeming to have a playful and laid-back attitude, Sei has experienced many tragedies in her life, especially in her second year. Sei's personality was very different in her first two years. She was uninterested in everything, and never joked around like she did in her third year. Her birthday is on 25 December.
- Shimako was asked by Rosa Gigantea, Sei to be her petit soeur.
- In the Rose Mansion, where the heads of the Yamayurikai have been meeting there every day to prepare for the school festival she winked at Yumi for pumbing into Sachiko easily, and said that she was surprised by how much energy she have, and that she's pretty good.
- When she looked at Yumi she could tell right away that she's a fan of Sachiko's.
- For it's not fair to force Sachiko to play the role of Cinderella at the school festival, so she gave Sachiko a chance by having her play a penalty game, if Sachiko wins she can drop the role, the bet was whether or not Sachiko can make Yumi her petit seour until the day before the school festival, getting Yumi who has turned her down to accept her rosary was her task. And so that Yumi don't take the Sachiko's rosary just to help her get out of the role, if Yumi accept her rosary and the role opens up, Yumi will be the one to play Cinderella, she's Sachiko's soeur once she accept her rosary, in order to make Yumi do her job to fill a hole left by her Onee-sama. Then more than a bit between Sachiko and the roses, it was a contest between Yumi and Sachiko.
- To make Yumi used for dancing, she took her hand to play Cinderella's waltz dance of course before touching one of her pigtails to earn her attention before dragging her into the dance, she also hugged before the dance, and whispered to her ear while holding her shoulders from behind.
- The separate personal reason she have for why she choose Shimako to be her soeur is kept as a secret.
- While sitting near the window, the good metaphor which she said to Sachiko and remembered about Yumi: that she's a "straw" that Shimako grabbed upon a chance encounter, she laughed and said that it was a great one, explaining the good part is where Sachiko keeps holding on.
- To her thinking she thinks that Shimako might be the one who envies Yumi, for she wanted to see Yumi's cute funny faces as she crept closer to her to embrace her before Sachiko entered the room they were in.
- When Sachiko entered the room she was embracing Yumi with a scornful face, she drew back to say that she did Sachiko a special favor because she saw her coming in.
- While she was left alone with Yumi at the dance rehearsal grounds, she held her waist from behind before she sprinted to search for Sachiko, asking her if she likes Sachiko then patted her head.
- Before the review session meeting in the Rose Mansion at eight o'clock she cuddled Yumi since she was right in front of the door, they still made it in time, and also she interjected her hand inside the collar of her upper uniform to discover the rosary of Rosa Chinesis en bouton.
- To wipe around Shimako's mouth using her handkerchief is what she wouldn't do as she notified at the review session, but if it were with Yumi she would love to coddle her.
- Before the Roses Election she approached Shimako who was about to be on stage to touch her face and give her some words of encouragement.
- In front of the statue of Mother Maria one Saturday, she told Shizuka that she is an enchanting person, and wished if they could have met each other a little sooner, perhaps they could have been closer to each other.
- As a parting gift she gave Shizuka a kiss on her lips after pronouncing her name as requested by her.
- After the Roses Election she hugged Shimako for she was nervous.
- The way she behaves towards Yumi if they were alone in the Rose Mansion is what she only do it with her, like when she smooched her cheek while embracing her from behind the time Yumi was washing the tea cups, nonetheless she had never considered to hug her own imouto, Shimako.
- Yumi in her view is so soft and huggable she thinks she might become addicted.
- Rosa Canina is pretty in her view that she talked about how pretty she is for two times, then after Yumi stopped walking and cried denoting herself in the same time as she supposed Sei to be putting her support behind Shimako, Sei's little sister instead of Rosa Canina, became she's her soeur, regretting that both of herself and Sei just silently stood by and watched, that was beyond sad to her that she cried, Sei then caressed her head saying that she was only saying that she wasn't going to interfere with Shimako's decision whether she wants the position or not, if Shimako wants it then Shimako herself can do something about it on her own, and if she doesn't she can just not run.
- The person who suggested to make Lillian school Valentine event so it's only the boutons who are participating is none other than herself, that way, every girl except the boutons could take part in the treasure hunt, for she was thinking it wouldn't be a bad deal for Yumi and Yoshino, and she conceived them that they wanted in a hundred chance to try to get a date with their big sisters, Sachiko and Rei, then winked at the petite soeurs.
- She was the first person who noticed Yumi have been sneaking around, doing chores in the Rose Mansion, and then going home before anyone see her.
- After she have been accepted by the school of her choice, she let Shimako know before anyone else.
- In the main room of the Rose Mansion, she suddenly embraced Yumi after she discovered Sei was to participate in the treasure hunt as well, so as to she can hardly just stand by and watch something that fun, plus she have been telling Yumi for a while to keep it to a little shriek, as she pursued her through the main room in the presence of Shimako, before Sei opened the door looking critically at her.
- She dragged Shimako out of the Rose Mansion since Rosa Chinesis en bouton and her petite soeur were quarrelling.
- The greenhouse isn't exactly a favorite place of her, because it's related with her past broken love with Shiori.
- To hear Yumi's appreciation words, she was flattered then she moved her hand to touch her head, tranquilizing her it'll work out somehow for her relationship with Sachiko, and advised her to express her true feelings to Sachiko a little more, and as long as she become able to do that, she's sure Yumi will be able to overcome whatever else may happen between her and Sachiko, and that was the assigned homework she consigned to Yumi, to reconcile with Sachiko on her own.
- The evening before Valentine's Day she was wistful for Yumi wasn't going to give her any chocolates.
- After she was told by Yumi while they were walking together to receive her petite soeur's (Shimako) chocolates rather than herself, she suddenly embraced her playfully, promising that if Yumi don't give her chocolates, she'll eat her.
- Only because Yumi was looking so intently at the door of the room she thought Yumi hid her Valentine's chocolates in, she ate it and thought it was a really delicious marble cake, though the inexperience showed and it was a bit lopsided, it was pink wrapping paper with rose patterns, though what was in the back of the room on the first floor was not the white card, neither Yumi's chocolates, but Shimako's chocolate cake that she had left there, and who was still undecided about whether to give it to Rosa Gigantea or not.
- Walking on Valentine's night with Shimako in Lillian school grounds, precisely near the statue of Mother Maria, she told her that she's lucky to have a person with a strong character as to refuse to eat chocolate bon-bons as Shimako.
- When Shimako was crying for she didn't want Sei to leave Lillian Academy, she prevented her from crying by taking her hand to insert inside her coat's pocket, gazing directly and closely at her face, she said that the marble cake she made for her on Valentine's Day was delicious.
- She accepted Shizuka's Valentine chocolate bon-bons, and she was willing to eat it with Shimako to warm themselves up in the cold weather, then after it started snowing again, she continued to walk together with her, with Shimako's hand inside her coat's pocket, and with Shimako's head resting on her shoulder.
- The author Sei Suga who wrote "The Forest of Briars" about a girl named Sei who fell in love with Kaori, who would put it to slumber, quietly and eternally, so even now, this forest presents an unyielding rampart of briars, and continues to deny entry from the outside, and it'll probably do so until the time of her death, the novel shares similarities with with Sei Satou's past.
- Right after Shimako mentioned the incoming Christmas, she stopped walking, then when Shimako questioned her, she said that she doesn’t like Christmas, because it's related to the day she lost Shiori the previous year.
- "The Forest of Briars" was a novel put out by Sei Suga that relates her hidden past in unreserved fashion, (Were those few months spent at the academy a dream?, Sei locked away everything in a forest of briars in her heart, it was a shocking autobiographical debut piece by a promising new author. Rosa Gigantea's past is like taboo in which people try to steer clear of it, it's like an onspoken agreement in which those who know of the circumstances at Lillan's Academy all keep quit, and have a way about them like they're being protective.
- Near the Non-Curricular Guidance office she was called to in discuss about her being suspected as the author of the love novel "The Forest of Briars", once she came across Yumi there, she hugged her by sticking her forward body against hers, playfully doubting if Yumi did report her for being a serial hugger, then brought her face close to hers, before retreating quickly as soon as the door of the office was opened.
- If Shimako wished for it, she'll keep her company in her embrace at the Rose Mansion from the evening until morning of the next day, because she worried if Shimako take it upon herself to bear the sadness of their separation, she'll be emotionally crushed, so she requested her to show some vulnerability.
- One sunset before she leave Lillian Academy since she graduated, she reminded Shimako of the spring that brought them together, and inspired her to look forward for the upcoming spring, when she'll meet new students and be Rosa Gigantea.
- She made a big fuss about Yumi who shoved her nervously at Minako's forced request for the newspaper club, that she said she couldn't hold Yumi any longer, and demanded her to step away, for besides tumbling into the Non-Curricular Guidance office locked in each other's arms would cause a lot of attention towards them.
- Locking Yumi between her arms, she demanded Sachiko to let her borrow Yumi, and then she playfully mentioned that she won't strip her of her uniform and toy with her or anything, she also borrowed Yoshino to tell them about her past love.
- Her hand was landing on Yumi's chest after the attention was directed to the Rosa Foetida en bouton and her petite soeur.
- The reason why she kept on playfully teasing Rosa Chinesis en bouton and her petite soeur is because she founds the way Yumi reacts is great, plus she enjoys seeing how Sachiko responds, they're twice the enjoyment in one bite to her, that she put her hands together gratefully.
- Her understanding point of Shimako is that if she wanted to stay and join the petite soeurs to hear about her past love, Shimako is the kind of girl who'll stay of her own will, even when she's told not to.
- By detaining the petite soeurs to treat them to ramen, and asking them to bring her a drink, it was just to read the girls' love novel "The Forest of Briars" in short order.
- Shiori Kubo is the girl whom she cherished more than her parents or siblings, and loved her so much, she felt like if she had her she didn't need anything else, Shiori was a pure person, who was thinking of becoming a nun, but one year ago on Christmas Day, she lost her, that is kinda the same as Sei and Kaori in the "The Forest of Briars", yet it's not exactly the same; in that she never left on a journey with Shiori, nor did they take sleeping pills, Shiori transferred schools.
- Sitting alone near the window at sunset, she was feeling wistful because she hadn't spoken the name "Shiori Kubo" in a long time until just formerly.
- If suffering for Shiori is what she have, she'll never yearn for another person again, in the winter of her sixteenth year, she experienced a painful parting that cut her to the quick.
- The first time she met Shiori was on a spring day, that morning she had arrived at Lillian's school far earlier than normal, and entered the convent to see her, she thought she was so mature, and seemed to her full of the warmth that she lacked.
- The first time Youkou heard her utter a person's name was "Shiori Kubo".
- Since she met Shiori she believed something had begun to change within her.
- With just that the previous Rosa Gigantea wish to Sei to stay by her side, because she wanted to see her face, she decided that she would be her petite soeur, because she found that simple and clear reason appealing, and the previous Rosa Gigantea was adapt at handling her, right from the start.
- After she knew Shiori, she became assertive , to the point where she even surprised herself, everyday witnessing her in the same convent, from the first time she met her, Shiori was there, as if she belonged there, and viewed her as a white, shining presence loved by this world, she came to see her because she wanted to so much, she asked her if she find her feelings bothersome, she laid herself there and thew herself on her mercy, there was no turning back.
- For the fact Lillian Academy had brought Shiori into her life, she was moved to thank God from the bottom of her heart.
- She spent as much time alone with Shiori as they could, and also became even more withdrawn from the Rose Mansion, and she lost herself in Shiori.
- The reason she lied to Youko of thinking about making Shiori her little sister, is because she had no intention of it in her heart, she secretly laughed at the soeur ceremony as something for people who needed symbols to reassure themselves.
- Walking together with Shiori after she ran to meet her in the convent, with both of their hands that they were born with were probably clasped in the hands of the same person, and as a result, they completely excluded all else.
- In an isolated place inside a forest, she embraced Shiori and said that she just wants to be with her, that's all she wanted.
- Waiting for Shimako to join her after her supplementary swimming lesson, it started raining suddenly, she grabbed her hand and lead her inside Lillian's greenhouse, it was the place she wondered why they were born as a separate individuals, after Shiori leaned her head on her shoulder, so she braided her tress along with hers, then after Shiori realized what she was doing, she urged her to sleep for a little longer, promising to wake her up when the rain stops, their hands interlocked, and hoped the rain won't stop.
- She wished time would just stop inside Lillian's glasshouse, on the ground that she wanted to melt together with Shiori and disappear, yet what she felt was unknown to her, of needing Shiori other than her own self, and questioned herself where it will ultimately lead, even if she will likely would never find the answer to her question, that's fine to her, because the only things that are certain to her were Shiori's heartbeat, Shiori's physical warmth, and Shiori's breath, and that was all that she desired in this world.
- In autumn of her second year at Lillian Academy, Shiori's place in her heart grew ever larger, and she increasingly spent less time at the Rose Mansion, to the extent that she suggested the previous Rosa Gigantea to sever her ties with her as her soeur, and find herself a new little sister.
- Just as she heard from Youkou about the probability of Shiori going away to join a convent once she graduated since she was going to become a nun, instantly she was in a bewilderment and a shock, that she ran to the convent, confessing her love passionately to her, and questioned her if what Shiori truly wanted was just a relationship until she graduated, and if that was casual for her.
- She was much agitated and angry with Shiori after she knew she herself who decided to be a nun and leave Lillian school, because she believed Shiori chose God over her, even though she have only Shiori as she informed, and didn't bear the notion of Shiori abandoning her.
- Because Shiori won't look her in the eyes, she suspected that she was wavering, wherefore she confessed her love to her again while holding her shoulders, then printed a kiss on her lips, before Shiori dislocated her with a push.
- She was feeling heartsick after she had lost to Mother Maria in earning Shiori's love, hence her attitude in class grew worse, and on the day of the closing ceremonies, she received a summons. The next year, she picked Christmas Day as her own birthday only.
- After Shiori gave notice that she would be spending nights away, and she couldn't be found at the dormitory or the convent, where she was likely to be, to spend those only two days without her, forced her to be in a yearning status to see her, that she almost cried.
- After only two days of her continues departure with Shiori, she received her in her lap hugging her, then shared a kiss on the lips with her.
- What she planned to do after she reunited with Shiori after two days while their hands were interlocked, is to run away together with her somewhere they don't know, and live without anyone bothering them, and requested her to pack her things and come, so she'll wait for her at the train station.
- Shiori saw her off with a smile the last time she saw her, she'll not forget that smile, never will she forget it.
- With the end of Christmas Eve at the train station, she awaited Shiori for three hours but she wasn't coming, yet she was unable to leave the train terminal, because she assumed Shiori might come down the stairs that time, and she was unable to abandon that faint hope, even if it was in a dream, she wanted to see Shiori.
- She cried on the lap of the previous Rosa Gigantea after she knew from the letter she brought that Shiori won't be coming, wishing she had never met Shiori of her heartbreak, and wasn't willing to imagine a future she has to make without her.
- Calling Yumi at the first day of a New Year, she questioned her if she hoped, even for a moment, to know it was Sachiko.
- Inviting Yumi to carry her by her car to the Yamayuri Council New Year's Get-Together, her plan was to have a date with her.
- Grabbing Yumi from behind while she was standing and waiting for her, she smiled and winked at her, and imagined that she sounded like some monster baby.
- Driving into Ogasawara's residence, with Yumi riding in her care, she questioned if she was happy because she wanted to see Sachiko, her role was to bring Yumi along to Sachiko's house and make things merry, she knew things would be lonely at Sachiko's house, so she brought Yumi.
- In the kitchen of Ogasawara's residence, she fed Yumi a takoyaki, and then wipped off some which was around her mouth using her handkerchief.
- Right after Kashiwagi tried to make a move on Yumi with a wink, she admonished him of going after Yumi.
- Jogging straight to embrace Yumi, she believed Yumi have been wanting to see her, and that what Yumi wanted her to do, because she got that feeling Yumi was calling for her.
- Calling Yumi to trick her into believing of the first-year students perform for the graduating students including herself, she told her so "her darling Yumi" won't be caught in a bind when she's suddenly asked to perform.
- Entering the infirmary Yumi was crying while having a bentou, she took charge of her to take her home, since her class is in study hall, and her mistress Sachiko asked her to do her a favor, she also pat her back, and was hesitating to leave her, and to never see her all the way home, so she handed her a drug to help her retrieve her energy.
- Staying in the classroom to say good-bye to it after she killed time in the library and came back when she figured that everyone would have left, she patted Yumi's head after she demanded to do anything she can for Sei, any requests or favors or promises Sei want to entrust to her before leaving Lillian Academy, something to do with Shimako, for example, while she tell her there's no need for herself to will anything.
- As a parting gift for graduation, she asked Yumi while still inside an empty classroom for a kiss on the lips, and she wouldn't let her run away, since Yumi said she will do anything for her, touching Yumi's chin she approached her closely to fulfill her demand, and asked her to be good and close her eyes.
- In the empty classroom, she teased Yumi over that if she doesn't hurry on home, she'll come after her again.
- Just after Yumi returned to her after resolving to cut the scene in which she was about to be kissed by her, and smooched the part near her lips, she chased after her before she ran away from her again and grabbed her between her arms, she didn't think it needed to be said in so many words, so she'd kept quiet, but she informed her that time she feels glad that she got to know her from the bottom of her heart.
- In her third year of high school, she was able to change in a good way, life has become quite a bit more bearable to her, there're a lot of reasons as for why she was able to change, Yumi was a big part of it, so she let Yumi know that she what she have done for her isn't just a kiss in that empty classroom, wherefore she requested Yumi to open her ears wide and listen carefully the case in which Yumi made her a college student, seeing Yumi, she decided to try being a student again.
- Hugging Yumi, she let her know that she loves her, and that she was truly happy when she got to goof around with her.
- For Yumi to enter the empty classroom she was in, she was thinking she might have been running around trying not to hear the name of the college she will go to because it would be like the college was stealing away her beloved Rosa Gigantea.
- She bid the empty classroom she was in good-bye, touching the place Yumi smooched near her lips.
- Because Yumi obliged to drag her somewhere where they can be alone to discuss about the college Sei was to enroll to, it sounded good to her to pick up where they left off the previous day.
- Yumi's embarrassed ablaze face is what she would have loved to see.
- Teasing Yumi by representing the smooch Yumi gave to her the previous day as the matter she intentionally kept from Yumi instead of the name of the college she is to enroll to is what made Yumi highly embarrassed that she covered her mouth with her hands.
- For the graduation ceremony, Tsutako took a photo of her embracing Shimako in front of the statue of Mother Maria.
- For a moment after taking notice of Shimako for the first time, she got startled because she thought it was Shiori, then she soon found out the name of that first-year student to be Shimako Toudou.
- Youko succeeded in perceiving what was in Sei's heart even more accurately than she could as always, about Shimako being a significant person to her.
- To her, Shiori was an angel, but Shimako in her opinion is human whom she gaze upon from a place slightly apart, that's all she wanted because that feels comfortable for her.
- She couldn't let Sachiko have Shimako, so she resolved to make Shimako her little sister, because she's the one who first found Shimako, plus she was just sure that she wouldn't accept Sachiko's rosary because she thinks she's better for Shimako.
- Just when class was about to start she dragged Shimako out of her classroom to lead her to a place where she would give her Rosa Gigantea's rosary, she thinks she'll probably be perfect for Shimako, yet she won't impose any limits on her.
- She tied her rosary around Shimako's wrist to make her her soeur, then dragged her back to class.