If you mean Sora from Yosuga no Sora, what we found is that she has a twin brother named Haruka.
Despite appearing similar from a physical standpoint, their spirits and personalities are fundamentally different, and the older of the two, Haruka Kasugano, tries to make the most of things to protect Sora, while adapting to life with familiar company.
Yosuga no Sora (The Sky of Connection) is a Japanese romance/drama adult visual novel developed by CUFFS ("Sphere"). The game was originally released for Windows PC on December 5, 2008.
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