((Everyone in this world is born with a trait, and your little sister (not blood related) Katie isn't different, she was born with the height trait, she is 15 years old and is already 50ft tall))

You were walking on the school when your sister stops you

"Hey Oni-chan... I forgot my lunch... Can I have yours?"

She does a cute face

She eats almost 10 times more than you because of her height