Big Brother (Wataru Minakami)
The big brother whom all of the sisters adore and the player character in the Visual Novel. He looks after his sisters and devotes an extraordinary amount of time caring and guiding them.
- Big Brother Instinct: In both versions, though in the anime, he was a bit reluctant at first, still weirded out at discovering he has twelve sisters.
- Catchphrase: In the anime: "It can't be true."
- Ordinary High-School Student: Wataru was this where he was trying to graduate to the school of his dreams, but instead, he finds himself on an island with twelve doting sisters.
- Promoted to Parent: It's quite obvious in the anime considering Wataru has to look after twelve of his sisters, but it's explored and justified more in the PSX games. There, the father is not present in any of the sisters' lives, and their mothers have high-class jobs which takes them away from spending time with their daughters. Therefore, the big brother has to step up and look after the sisters with not just love and attention but also parental guidance.
The following are tropes that apply to all the sisters:
- Big Brother Worship: Justified in the PSX games where the sisters' and the brother's father slept with 12 different women and had the sisters by them. He's never around in the growing up of the girls, and while luckily the sisters' mothers aren't in any financial trouble due to their high-end jobs, they aren't there to provide emotional support. This is where the big brother steps in, and hence why the sisters adore him so much: it's because he's not only giving them love and attention but also parental guidance.
- Parental Abandonment: While not outright stated or alluded to, in order to keep the games' and anime's sweeter mood, the reason why the sisters adore their brother so much can be seen because of this. Their father is never around, and their mothers are too busy with their high-end jobs. As a result, their brother has to step in.
- Western Zodiac: Each sister is born under a different sign of one.
Aria
A soft-spoken girl from France who enjoys sweets, particularly parfaits, likes wearing frilly dresses with bows and lace, and tends to cry whenever there is trouble.
- But Not Too Foreign: Half-French, half-Japanese.
- Catchphrase: "Kusun" when about to cry, which is the onomatopoeia for sniffling.
- Third-Person Person: Refers to herself like this, which is considered childish in Japanese culture.
Chikage
Occasionally gothic, mysterious, and aloof, she is a practitioner of black magic, however, she prefers using those forces for subtle methods rather than brute power.
- Butterfly of Doom: Is seen quite a lot with butterflies in her imagery, alluding to her mystical nature.
- Catchphrase: In the games, she has "Ya, anii-kun" when greeting the brother.
- Dramatic High Perching: Stands on a lamp post in her first appearance in the anime.
- Hermetic Magic: Her style of magic, complete with tarot cards and even a crystal ball.
- Lady and Knight: In the anime, Chikage believes she and Wataru may have been this respectively.
- Reincarnation Romance: The reason for Chikage's feelings towards her big brother are due to this where she believes that in a past life, they were lovers rather than siblings. However, the reincarnation cycle messed up, so Chikage wound up as a younger sister instead. In the anime, Chikage takes it to stride and decides to wait for the next life to try again. However, in the PSX games, due to the twist ending that it's found out that the sister of the player's choice is not blood-related, this can be seen as this or possibly Schrödinger's Gun where this only applies in Chikage's route.
Haruka
Coming from Germany, she aspires to be a perfect Japanese lady, and is frequently seen wearing a kimono and practicing various Japanese customs.
- But Not Too Foreign: Half-Japanese, half-German.
- Yamato Nadeshiko: Despite being part German, Haruka aspires to be the perfect Japanese lady and is seen wearing a kimono, practicing tea ceremony, and trains with a naginata which is a weapon that the wives of samurai are accustomed to.
Hinako
The youngest of the sisters, she is very child-like and shows her affection accordingly.
- Third-Person Person: To emphasize her young age and childishness, though she calls herself "Hina", dropping the "ko".
Kaho
A bit clumsy, however, she is part of the school's cheerleading team and loves to cheer her brother on.
- Cute Clumsy Girl: Kaho tends to trip over a lot and is pretty clumsy. This gets deconstructed in one of the games where she gets chastised and scolded for her clumsiness which is messing up a cheer routine.
- Genki Girl: Cheerful and excited, which fits with her being a cheerleader.
- Third-Person Person: Addresses herself as this in the Japanese version.
Karen
A skilled pianist, she is sweet and gentle with her personality making her seem more like an older sister rather than a younger one.
- Elegant Classical Musician: Plays the piano.
Mamoru
Incredibly athletic and very tomboyish, she's an avid sports girl who tries to get her brother to play sports with her.
- Catchphrase: In the games, "Yaho, anii!" in greeting to her big brother.
- Tomboy: Looks and dresses like a boy and enjoys a wide verity of sports.
Marie
Possessing a sickly constitution, she spends a lot of her time in hospital due to her illness. She has a pet Golden Retriever named Michael who keeps her company.
- Delicate and Sickly: Often gets sick a lot due to her weak constitution.
Rinrin
Spending most of her time building things, she constantly asks her brother for monetary donations for her projects. Regardless, she is still quite skillful with technology and science.
- Gadgeteer Genius: An ambitious inventor who can create all kinds of technology with little resources. Case in point, she makes home-built laptop PC's with a custom operating system overnight for literal pocket change.
- Humongous Mecha: She built one called Mecha Rinrin.
- Perpetual Poverty: Rinrin constantly asks her brother for monetary donations for her projects.
- Robot Girl: Rinrin makes one and calls her Mecha Rinrin-chan.
- Transplant: Technically, She becomes one
when she joins the cast of Summer Radish Vacation 2 as "Rin", which takes place several years before School Days. Despite that, she is not seen nor referenced in School days itself
Sakuya
Into fashion, she is pretty much a typical modern teenage girl. She would rather her brother see her as a woman rather than his sister.
- Clingy Jealous Girl: Tends to hold onto Wataru's arm in the anime. Interestingly enough, this attitude isn't displayed against her sisters but rather his male best friend.
Shirayuki
She really loves to cook, especially if it's for her big brother. And so, as a result, she always tries new recipes for him.
- Lethal Chef: In the anime, Shirayuki is this initially, though her cooking is more strange rather than inedible or bad. However, she later becomes more adept at it as long as she's happy.
- Meaningful Name: Shirayuki literally means "snow white". The fairytale Snow White is also called Shirayuki-hime. Additionally, Shirayuki also addresses herself with the "-hime" pronoun in the Japanese version.
- Supreme Chef: In the games, meanwhile, Shirayuki is this instead where she goes to school to give her big brother her homemade meals.
- Third-Person Person: Shirayuki not only addresses herself with her name but also adds the pronoun "-hime".
- Verbal Tic: Ends her sentences with "desu no" in the Japanese version.
Yotsuba
Coming from England, she fancies herself as a detective à la Sherlock Holmes, and can be found with a camera and magnifying glass.
- But Not Too Foreign: Half-Japanese, half-British.
- Catchphrase: "Check!"
- Genki Girl: Gets quite easily excited and is pretty energetic.
- Wearing a Flag on Your Head: The Union Jack.
