(Pronounced Ka-ZOO-Yah Ma-Key-She-Mah)
Biography
A natural athletic genius born with perfect reflexes and motor control. It's near impossible for him to make mistakes. Excelled in any sport he played with little effort, but settled on golf as his game of choice because he didn't need to rely on teammates who weren't able to keep up with him. His charismatic nature, success in his field, and silver tongue make him very popular, but they hide his true darker personality.
Personality
As the other students are soon to find out, once the public eye is off of him he displays his true colors. He is arrogant and cunning, and sorts people into winners and losers when he meets them and treats those he considers 'losers' with contempt and mockery. He is intelligent but trusts almost no-one but himself and dislikes co-operating with the rest of the group. The only qualities he seems to praise are self-reliance and ambition.
Voice Description
Kazuya should have a smarmy, medium to medium low voice. I have considered a slight raspiness to his voice.  Kazuya is an intelligent person, and he knows it best so the smugness in his voice should be pronounced but not to the degree that he sounds pompous. He rarely raises his voice when speaking normally but should have a tone like he is talking down to everyone. Despite all of that, he is still a smooth and persuasive speaker which lends well to his scheming and manipulative personality, occasionally even speaking flatteringly when he wants to. When mocking people he lets the facade drop and really tears into them with his arrogance and contorting his face as he jeers them and cackles. 

Keywords: Smug, Scheming, Charming, Persuasive, Manipulative, Intelligent, Arrogant.

Example Expressions: https://tinyurl.com/y7qvwaor