English ver.(Cp 3.4 )https://batotoo.com/title/124290-in-another-world-my-sister-stole-my-name
大学生の一花は、物置で手にした手鏡を通し異世界のセシルという少年と交流していた。
そんなある日、姉の華恋が突然失踪し、同じタイミングで手鏡も消えてしまう。

1年後、一花は偶然見つかった手鏡を手にした途端、異世界へと飛ばされていた。
そこにいたのは年上に成長したセシルと、なぜか一花と名乗り聖女となっていた華恋でー！？

姉に名前や思い出を奪われた世界で、運命を切り開いていく異世界溺愛ファンタジー開幕！
Ichika, a college student, was interacting with a boy named Cecil from another world through a hand mirror she held in her storeroom. One day, her older sister, Karen, suddenly disappeared, and at the same time her hand mirror also disappeared. A year later, as soon as Ichika picked up her hand mirror that she found by chance, she was sent to another world. There was Cecil, who had grown older, and Karen, who had become a saint by calling herself Ichika for some reason?! In a world where her name and memories are stolen by her older sister, a different world doting fantasy opening up for her destiny!