My brother is a bully and I'm a loner?!

The older brother didn't know that his younger brother was a bully, but when he found out, the older brother, who was a bully, scolded him and became a bully himself. Then, the younger brother became a bully and turned the older brother into a bully again. However, the two developed feelings for each other, and when they realized that they weren't related, they got married.