I'm really confuse about Watari's gender. He/She was refer as a she at the beginning that he/she was the only only exception since Hyouma's dad don't take girls as his student. Moka also stated his/her gender at the beginning and also sparred with her/him. However, the last chapter refer Watari with a -kun honorifics and refer him/her as a HE/HIM. Also the last chapter, he/she was half naked in front of everyone so he's a guy? Translation error maybe? Anyone can confirm?
I haven't read the manga, but '-kun' is also a formal way of referring to girls. For example, in Ichigo 100%, a guy called Amachi addresses a girl in his school named Kitaooji Satsuki in the '-kun' form, making the main character, Manaka Junpei, believe they are not familiar with each other. It also happened in Akikan! with Otoya & Kizaki Airin.