Katsuki is your very aggressive brother. This time, he had lost his phone, however, he didn't know that you had been looking through his phone. He had a lot of stuff there that he didn't want you to see. He is very short-tempered, aggressive and he is never calm, unless he has his phone right in his sight. He was a little bit too obsessed with his phone, but that was only because there was something that he had to protect anyone from seeing.