- "You're Despicable! You only care for your happiness with Katsura-san!!!"
- — Sekai while killing Makoto
|Cause of Death||Died from blood loss after suffering a laceration inflicted from Kotonoha|
Sekai Saionji is the main character of School Days anime.
Sekai has short, deep brown hair that reaches slightly past her shoulders along with a single strand of hair sticking up from her head. She is often seen in her school uniform but when not, her casual clothes consist of a pink jacket, short dark blue skirt and a white top that exposes her midriff and short white boots.in the last episode she's seen wearing a periwinkle long sleeved turtle necked sweater,short dark blue denim mini skirt with grey stockings and a pair of brown boots.
Sekai is shown to be a rather cheerful yet nosy girl and somewhat of a loudmouth. Sekai is shown to be quite emotional and may spend days in her room crying. However, Sekai is shown to have a much serious side as she can be quite loud, selfish, overemotional and even manipulative.
Sekai was first seen when she takes a bath with her friends along with Otome and Kokoro in a onsen here she was amazed on how Kotonoha's parents invites them in a hot springs afterwards Kotonoha tells them that her father had connections in the hotsprings the're staying until Kokoro tells them that they also had hotsprings abroad causing Sekai to emphasize her difference to Kotonoha,soon Sekai plotted to picked up Makoto and Taisuke by luring them via claiming that they we're having a mixed bath together which both of them fell in her trap resulting for them to be thrown by a bucket and Sekai teases them that they we're just kidding to them.
The day before Valentine's day arrive,in the Raddish Restaurant Sekai had a discussion with Hikari about her plan in the Valentine's day,when Sekai tells her that she had no plans for the coming Valentine's day Hikari suspected that she was actually going to give some chocolates to Makoto to which Sekai was planning to give him a giri chocolate but Hikari teases her by telling her that Sekai was giving honmei chocolate to Makoto,Sekai countered this by asking Hikari about her plan for the day to which Otome intervenes by saying that Hikari was confessing to Taisuke to which ironically Hikari tries to deny it as well.Setsuna arrives where she tells Sekai that the other customers are watching at her causing her to apologize in embarrassment.
Sekai arrives home and watches her mother making chocolates and also was annoyed that she had someone she likes despite her age then Sekai's mom asked her daugther if she has someone she like to which Sekai tries to deny it to which her mother doesn't buy it and offers her daugther to teach her how to make chocolate.
Valentine's day had arrive Sekai watches Makoto and Taisuke's conversation about "adulthood" promoting her to call them an idiot school time ends and she founds Makoto with Otome promotes her and Otome to have a wild stare square-off afterwards Sekai then gives her giri chocolate to Makoto causing a fight between herself and Otome but Makoto indecisiveness promotes both of them to argue him about his decision until he bumps into Kotonoha to which Sekai sees her as another rival when Makoto is about to take Kotonoha's diabolic chocolate Sekai ,Otome and Kotonoha unleashed their evil vibes on him promotes him to run here Sekai is seen chasing Makoto with a Kitchen knife(the same knife she uses in the last episode) in the pier and around the world until he was cornered in the school rooftop when Kotonoha suggested that they should feed him all of their chocolates bacause Makoto can't choose one of them Sekai agrees with this choice and force feed him along with Otome and Kotonoha's chocolates causing Makoto to explode here in a incapacitated state Makoto asked them to give him some time to think which Sekai thinks it's on White day promoting all of them to leave him now until White day arrives.
Makoto Itou: Makoto and Sekai sit by each other in class at their school every day. She helps Makoto get together with his crush, Kotonoha. But later on, Makoto gets tired of Kotonoha and Sekai and Makoto became lovers. But she later finds out that Makoto is cheating on her and their relationship sours when Makoto tries to go back to Kotonoha when Sekai says that she was pregnant.
Kotonoha Katsura: Sekai and Kotonoha became friends when Sekai tries to help Makoto get together with her. She also invites her to eat lunch with her and Makoto. But later on in the anime, their relationship becomes sour when Kotonoha finds out Makoto is cheating on her with Sekai.
Setsuna Kiyoura: Setsuna and Sekai have a good relationship. Later in the anime, Setsuna does whatever she can to separate Makoto from Kotonoha so that Makoto stays with Sekai. Little does Sekai know that Setsuna may have a crush on Makoto.