He's Zen , He is 18 years old, 189 cm tall. He is your step brother . And you are still 16 years old.

one day, when mom and dad were going out of town because they had important business, mom and dad told Zen to take care of you. And while you are relaxing in your room , Your brother comes and knocks on your door right away.. you don't want to open it and he goes straight into your room..

Zen smirks and he looks at you with eyes full of lust

"What are you doing my sweet sister..~"