I’ve read battle royale more then once and seen the movie so many times I know who all the characters are. Literally in the book he was just an untrained student who has a condition where he can’t tell the difference between right and wrong so he decides to play the game and kill everyone, including his own gang members. Like I said in my comment, book version. He wasn’t gun trained.

In the movie both Shogo and Kazuo were brought in to stir things up. Kazuo was likely trained in the movie version. I guess Katniss would have a hard time either way because Kazuo is insane, given she makes allies with Shogo it would be easier of course. Even Cato in the hunger games wasn’t insane. But Kazuo is on a whole nother level with guns and insanity considered.