|Voice Actress||Shiho Kawaragi|
Sekai is a lively classmate of Makoto Itou who one day discovered his crush on Kotonoha Katsura after being seated next to him. To make up for this she offered to help him get to know her, but her true intentions cause him to grow uneasy.
Sekai has an average frame but small bust with fair skin and big, midnight blue eyes. Her short brunette hair is nearly chest length with similar shaped bangs and a long, thin cowlick. Late in the series, it is noted that she has began to look thin and sickly.
Normally Sekai is depicted in the school uniform, and she is shown having a plain and basic, slightly feminine casual attire. During winter she wears an expensive winter jacket she was forced to save money to afford.
Sekai is a typical teenage girl. She is usually in a cheery and spirited mood and is normally dealing with common topics for teenage girls- like school, romance, friends, and work. She is genuinely kind but can be fairly nosy and pushy in her attempts to help someone. She also likes to tease others, and she has many friends due to her approachable nature.
However, she is also shown to be very passionate, bold, and stubborn. If someone messes up she has no problem criticizing their stupidity; and her lack of tact usually causes trouble for herself or others. She is also shown to be highly emotional, and when angered Sekai can become bitter and lash out towards those she blames responsible.
Her moral stability is also brought into question due to her impulsiveness. While she wants others to be happy, she struggles with trying to ignore her wants and desires, and is shown having a lack of guilt for her poor decisions later on. She is shown forgetting logic and is unable to consider the consequences of her actions, and is shown to be highly cowardly.
Deep down, Sekai is revealed to also suffer from depression and feelings of inferiority. She seeks the attention of those she cares about, and if ignored or left alone she struggles to function.
However, facets of her personality differ between media:
In the visual novel Sekai is selfless and friendly, and despite her feelings for Makoto she insists on keeping distance if he shows interest in her. She is shocked to find out her friends bully Kotonoha and it takes her a while to warm up to dating Makoto if he pursues her.
In the Anime, Sekai remains friendly but her selfish and impulsive traits are played up more. It is implied from the start that she has ulterior motives, and took to ignoring Kotonoha after she and Makoto hooked up behind her back. Initially she did tell Makoto off after seeing how much damage they have caused, but after he claims to have broken up with Kotonoha she gives in and resumes their relationship.
In the manga she is shown in her worst portrayal. Here she actively pursued Makoto, using any chance she could to bond with him until he agreed to break up with Kotonoha to date her. She was shown to be indifferent and cold at various points.
In a spin-off manga, she is shown to be on much better terms with everyone and got along with Kotonoha as a result of the threesome they are in with Makoto.
Sekai is revealed to have known Makoto since they were younger, through her close friend Setsuna. After she attempted to help Setsuna learn more about Makoto she gained her own feelings for him, and Setsuna agreed to bow down to allow Sekai a chance to be with him.
Sekai normally relies on her surroundings or a knife to attack others.
Unlike Kotonoha, who attacks others for the pain caused to her, Sekai focuses on Makoto unless pushed far enough to target Kotonoha instead.
For a full list visit Sekai's Relationships
Parents - Sekai lives alone with her mother and has a close relationship with her. She usually confides in her and has learned a lot through her. She despises her lecherous father for abandoning them.
Makoto - After getting to know him and witnessing his kindess she quickly fell for Makoto but struggled to approach him. But after the classes switched she decided to take a chance and offered to help him in hopes of getting closer to him. She has a tsundere-type personality around him but has no problem offering her body for him to "test" as a means of getting his attention- despite his frustrations with her. He found her annoying at first but had no problem using her for sexual purposes due to how reserved Kotonoha is.
Kotonoha - Despite her envy towards Kotonoha, Sekai has no ill-will towards her at first. She genuinely got along with her until Makoto showed an interest in the both of them and she was unable to deny it or confess to what she did. She doesn't seem to want to hurt Kotonoha, and expresses remorse for it unless Kotonoha eventually lashes out at her, or should she feel threatened, effectively ending their friendship at various points in the series.
They can become a threesome with Makoto in a spin-off manga and in one route of the original game. At this point, they are shown to act as they did prior to Makoto's confession to Kotonoha, with Sekai surprisingly becoming the hesitant and awkward one of the two.
Sekai can suffer through a few deaths in the game, and is killed during the anime final.
- Bloody Conclusion - The most common death for Sekai and the most infamous for the series. As she, Makoto, and her friends walk across a bridge they are approached by the mentally broken Kotonoha. She attempts to kindly greet her, unaware of the danger and is unable to react in time to avoid having her throat slit by the weapon Kotonoha was holding. Sekai bleeds out violently and falls over as everyone reacts in fright
- Innocent Evening Sun - Pulled on the train tracks after she pushes Kotonoha down. As they begin fighting, neither girl sees the approaching train and are both hit by it.
- Twisted Hair - Like above, but this time Kotonoha lives. As Sekai tries to escape the tracks her phone falls down and as she tries reaching for it, Kotonoha uses her body as leverage to get to safety with Makoto's help. Just as Sekai grabs her phone the train collides with her.
As Sekai learns she is pregnant, Makoto and Kotonoha were beginning to reconcile. But as she tries to make him take responsibility, they try to convince her to have an abortion with no remorse. She refuses and starts to harass Makoto until the stress causes her to become depressed. She makes one last desparate plea after confronting them when they return to his place from a date, but after getting angered she slaps Kotonoha, causing the fed up Makoto to tell her off and passionately make out with Kotonoha in front of her until she leaves.
The following day at school, she convinces Makoto to speak to her and they agree to meet at his place. At first things go well until Makoto brings up the pregnancy and suggests abortion again, causing them to argue until he calms her and offers to grab her a drink. She agrees, but requests getting it herself. She heads to the kitchen and uses this time to grab a knife, sending him a text. As he reads it with confusion, she attacks him and stabs him in a blind rage several times until realizing what she has done. Alarmed she runs away and hides in her room until she gets a text from Makoto, asking to meet up.
Expecting the worst, she heads up to the roof of a building to find Kotonoha there waiting for her with a bag, which she shows to be holding the decapitated head of Makoto. Shocked, Seika is physically ill and snaps at her before trying to attack Kotonoha after realizing she planned on harming her. However, she is unable to react quick enough and is killed by Kotonoha, who then slices her open to see if she really was pregnant before leaving.
"Makoto-kun, Help Me!" - mockinginly quoting Kotonoha in the Manga when telling Makoto about killing her.
- Due to her behavior and greed, most fans see karma getting back at her in the spin-off games. While Kotonoha remained a main love interest, Sekai ended up becoming a side character with a lack of involvement and endings, inlcluding one game that wrote her out for a good part of it by saying she was sick. Her routes and endings were given to her Mother and other possible Love Interests.
- Some fans have compared Sekai to Kagome from Inuyasha.
- It has never been revealed if she was really pregnant or the game or anime. While Kotonoha sees no proof of it in the Anime, it has been pointed out that it was too early for physical proof to have formed.
- It was also possible it was Sekai's own, damaged mental state that made her think she was pregnant. Or that Kotonoha was denying it.
- Her voice actress provided voice samples for one of the types of Yandere personalitieas in Artificial Academy.
- It has been noted that Sekai slightly resembles Makoto. With the complicated family charts between the game series made by the company, they are revealed to be non-blood related siblings or cousins through her father.
- Sekai's attack on Makoto and her death scene were altered in the airing of the final anime episode, with the blood shown being black and less detailed. In the DVD versions, the blood is red like it was originally intended to be.