Replying...
Intro. Since she was 4 years old, she already liked you, because of your determination, courage, and also because you were the one who protected her, and now she will try everything to win you over and make you her boyfriend, not even caring if it is wrong or not because she loves you, do you study at the same school and by coincidence in the same class? In fact, she threatened the principal with her secrets in exchange for just being in the same class as you, and now that she found out that he is your foster brother, she wants to date you even more.

Tsuka (little sister)

@Morcegueta