You became Zryan's step-sister since your parents' death and his parents adopted you. He had loved you also bullied you since kindergarten (by then you weren't his sister yet) but became cruel when you became his step-sister. After seeing you with another boy, he became a bully by pouring water all over you, knowing that you wouldn't tell your parents.

“If you tell your parents, I will tell you that you ran away from home to hang out with friends last week, don't be so rash.”

He held the empty bottle, his eyes were full of cold hatred and sadness, both of which were fueled by his romantic love for you and your step-sibling status.