| Sora Kasugano|
|First Appearance||(Anime) Episode 1|
|Portrayed By|| |
Sora Kasugano is the main female protagonist and the twin sister of Haruka Kasugano.
Sora is a very beautiful white-skinned young girl who has a perfect, doll-like appearance and is often seen as a fragile and weak girl with long silver hair that is tied in twintails and gray eyes. Whenever she goes to school (or some other places) she often uses this twintail hairstyle. She usually unties her hair once at home. She is 152 cm tall and is often seen carrying a rabbit doll, which she received as a present from her mother before she and Haruka Kasugano left the village and which lends her a deceptively childlike character. She wears black ribbons for most of the Anime and Visual novel, but is shown to wear white ones when she was younger, and later on in Haruka no Sora.
Sora is a quiet, fragile and reclusive girl, fraternal twin sister to Haruka Kasugano. Yet beneath Sora's angelic doll like appearance lies a troublesome personality that is prone to withdrawn laziness and a rather severe lack of social graces. In episode 10, she becomes more considerate and caring towards Haruka after she decided to not trouble Haru too much and tries her best to take care of him. She seems to be very lonely when Haruka is not with her. Also she is very jealous when she sees Haru with another girl. In the manga she tends to be more helpful and caring towards Haruka, like cooking when he can not and she does not seem to spend too much time on internet. But, besides Haruka she seems to act friendly towards Akira Amatsume too.
The traumatic loss of their parents, Sora's deep bond with Haruka Kasugano and a kiss she shared with him as children causes her to fantasize about him. While she shields the extent of her feelings for him in public, she experiments with herself while fantasizing about being with him. She hates Nao Yorihime because of her relationship with Haruka and the fact that Nao raped Haru when they were young. Although she hates Nao, it was implied that they were once good friends.
At the end of her route, she wins Haru's affection by confessing her love to him and making love to him as he was caring for her when she had a fever. After they get caught making love by Nao and Kozue Kuranaga, he attempts to break off the relationship and she attempts suicide by drowning. Haruka tries to stop her but his inability to swim only causes the both of them to sink. Sora changes her mind upon hearing him whisper "save me" and she drags Haru to shore. Afterwards, they decide to travel to a far away country, they are travelling together, and they love each other and decide that they are the ones for each other, promising their friends to come back with souvenirs.
- Mr. Kasugano (father) (deceased)
- Mrs. Kasugano (mother) (deceased)
- Haruka Kasugano (elder twin brother/ lover/ husband)
- Grandparents (mentioned)
- Kasugano distant family relatives (mentioned in episode 12, while in the manga they are referred to as friends of their parents in Vol 2. Ch. 14 - Faraway Sky)
- Kasugano family friend (an artisan mentioned in episode 12 with whom Haruka and Sora went to live at the end of the anime)
- Nao Yorihime (They were friends in the past, but Sora caught Nao having sex with Haru, which is the reason why she hates her.)
- Akira Amatsume (In the manga, often intervened with Haruka on Sora's behalf)
- Kazuha Migiwa
- Motoka Nogisaka
- Kozue Kuranaga
- Haruka Kasugano lover (Yosuga no Sora) / husband (Haruka no Sora)
- The name Sora means "sky" (穹).
- Like Motoka Nogisaka, Sora seems to have a high libido. This is proven by the fact that after the first time she had sex with Haruka Kasugano, she was eager to do it "many times again". Sora is also inclined to initiate sexual activity with Haruka before and after school sessions.
- Sora is portrayed as heavily dependent on Haruka in the beginning.
- Sora is almost never seen without her stuffed rabbit doll that her mother gave her when she was hospitalized in the anime, while in the manga it is Haruka who gifts it to her at the hospital.
- Sora is the only character who has attempted suicide.
- Sora goes to great lengths to seduce Haruka or at least to get his attention.
- Sora spends most of her time surfing the internet, being shown using an allegory of the real life 2chan, a popular Japanese imageboard dealing with otaku and underground culture. Haruka describes her by saying "She can't live without it", when Sora pesters him for Internet connection in their home.
- Sora enjoys consuming chips and other various snacks, often eating all snacks in the house, much to Haru's chagrin.
- Sora seems to have a preference for Pocky as shown in the opening scene in both the Anime and the Visual Novel, where she enjoys a box with Haruka.
- Sora is the most outright antisocial character of Yosuga no Sora.
- While having different names, the VA for both the anime and the game are the same, Haruka Shiranami is a pseudonym for Hiroko Taguchi
- Sora wears a steel or silver cross with catholic design, though it is shown she does not wear it at times, and never at school.