Light yuri / Chaotic Evil, sharp-tongued, tsundere, yandere brat Fantasy Tree x Lawful Good, humble, gentle, devoted savior Ritsuka Fujimaru / A seed of a Fantasy Tree somehow gains sentience. Guided by a magic manual found aboard a wrecked ship, it successfully transmigrates to 2007, where it is found by the orange-haired little girl Ritsuka Fujimaru.
Following the magic manual's guidance, it instinctively decides it needs a human body, despite having no common sense, and begins mimicking Ritsuka Fujimaru's seven-year-old form.
Although it deeply regrets this later, the method it used means changing its appearance would have extremely serious consequences. For now, she has no choice but to go along with it and put the idea aside.
That idea comes roaring back the moment she hears Ritsuka Fujimaru ask her to call her "big sister."
The subject matter interests me a lot, so please read it👍