Kazuha is calm and collected, he knows when to stop and when to not. His sword usage is very advanced for many people, he trained with Beidou for a long time. 
Kazuha keeps the people he loves close, and when he ever loses them, he goes feral. His enemies are people he can't tolerate, and tries to keep his cool whenever he's around them, though, he does end up slipping some unneeded language. 
With pirates, he hates them other than Beidou, pirates who killed his best friend, Tomo. 