Original character of nakano youka, for "世回転界クロジカル (よかいけんたいくろじかる)" AKA "World-Rolling Black Logical" under series name 空狂少女 (からくりしょうじょ / Karakuri Shoujo), also written as "カラクリガールシリーズ [Karakuri Girls Series]".
Information comes from her profile on Uchi no Ko-Mato (stands for うちの子まと/うちのこまとめ [Uchi no Ko Matome]):
Profile
Quote: I don't know anything about the world
Name in Furigana: せかい (Sekai)
Works Appeared In: World-Rolling Black Logical
Age: appears to be 14 years old
Gender: Female
Height: 150cm
Weight: 40kg
First-person pronouns (personal pronoun): Sekai (see Wikipedia on use of name as first-person pronoun), watashi / 私
Second-person pronoun (referring to others): [Name]-san / 名前(さん)
Biography
Main heroine. Amber and sky-blue long hair, with cherry blossom pink pupils. (Because her hair has something like structural coloration, it shines gold when the light hits upon it strongly, and has a tinge of blue where it doesn't.) She talks in a manner like "-hoyo?", "hawawa", "~nano desu". Because there is no direct English equivalent for these, I left them as is.
She is a girl who came down from the sky and met Misaki.
She has a perfect appearance, like that of a doll:
according to Masaki Otome it's something like this — "In eighteen years of living, I've never seen a girl like this. Her cuteness is something that cannot be expressed in words"
has a face very closely resembling Rourin's, and was both looked over and intimidated by her. She has said that in order to escape from her, it wouldn't be overdoing it to hide in a room where light could never reach.
Referring to them as "vessels", she is in pursuit of every human being. She is hiding an unhuman ability. "...I don't know, I'm sorry"
With an innocent, absent-minded impression, she isn't sure what she should do or wants to do and so seems like a doll-like girl with nothing in her. Nonetheless, she isn't indifferent; she is openly moved by even small things, and shows a variety of expressions.
Contrary to her apparent age, her mental age is much younger.
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After leaving for this outside world and meeting Misaki and the others, experiencing and learning lots of things, eventually she was able to find her own purpose. In regards to Misaki, since Misaki was the first person she encountered in this outside world she considers herself indebted to her and thinks of her as her beloved, most important person.
Full of emotion and brimming with curiosity, she is more or less a clumsy girl. Basically, she's a friendly person and smiles at everyone. Being absent-minded, there are times when one isn't sure what she's thinking about, but generally she herself is naturally an airhead who doesn't really think about anything. She also occasionally has the initiative to straight-out tell you what she's thinking.
Due to her trauma from being locked up for many years and her anxiety that her body being taken over by Rourin, she has a relentless fear of "I will be lost".
She is a clone of Air. It's only been a small amount of time since she gained consciousness, and because she escaped without knowing anything, she remains innocent/ignorant. She fled from Rourin, who was using the "key of the world" entrusted to her by Noel, and came along to Misaki by chance.
She likes the blue sky, high-up places where you can see the sky well, and animals. She's good at climbing trees. She dislikes/is bad with dark, enclosed places. She is particularly afraid of the dark.
It seems like she is able to communicate with animals. The reason is unknown. She also makes friends with animals easily.
