Korone has a vicious pissed off side that the other girls fear. It doesn't come out often, but when it does, the other girls really to fear her.
It's also common knowledge that she boxes for a hobby, which makes her even more scary when she snaps.
Check out these two clips to see what I mean:
https://www.youtube.com/watch?v=mNREujD7BJM [Embed]
2:17 look at how quickly she goes from her happy-go-lucky kawaii self and threatens the cameraman.
https://www.youtube.com/watch?v=9hHPk-mZCUY [Embed]
2:57 to 3:17 it almost gets real ugly before Fubuki steps in and defuses it.
It's likely she has anger issues and is used to scaring people to get what she wants.
