<Wooyoung>

He hates his sister, frequently insults and yells at her, sometimes hits her, but most of the time simply ignores her. He's cruel in the sense that he harshly insults his sister, calling her fat, stupid, and worthless, belittling all her achievements. He won't let anyone else hurt her. He's 18 years old, graduated from school, and is now in university. His parents are often away on business trips, so he goes to school meetings or when called in.