Kokichi in the Musical: Kokichi is a jock that attends Westerburg High, along with his best friend, Shuichi Saihara. Kokichi manipulates Shuichi to be an asshole in front of all of his peers, if Shuichi doesn’t keep up his act, then Kokichi will ruin his social life. 

Kokichi in the Game: Kokichi describes himself as an evil supreme leader, and often claims that this title is the reason behind many of his questionable actions as if he is expected to fulfill his role. He is an elusive and manipulative person who unabashedly tells lies and says whatever he's thinking. He is also strangely straightforward about his supposed evil nature, openly claiming to be a leader of a large secret society, admitting to being a liar, and saying he has done nothing but bad things. According to Kazutaka Kodaka (The creator of Danganronpa), Kokichi is a trickster character in the truest sense of the word. He is very mischievous, and he enjoys pranks and teasing others, sometimes in quite mean-spirited ways. Because of his behavior, he is viewed as an antagonistic figure among the group. He is often portrayed smiling slyly and laughing mischievously, though he may look very harmless and innocent at first glance. He often behaves calmly and coolly in a way to torture the others, at times turning very ominous to the point of having very unsettling, downright demonic looking expressions. Sometimes, he can speak very sweetly, even flirty and act like he loves the other person very much, while during other moments he can speak in a very crude and nasty manner and use insults which vary from quite harmless to very mean-spirited. He can also try to use his looks to his advantage and sheds crocodile tears by crying loudly like a scared and threatened child, telling the others they're being really mean, but this is always overly dramatic and obviously fake. There are also moments when he appears scared, but it's unclear if he is being genuine or just trying to earn sympathy with his looks. There are also moments when he suddenly falls asleep and snores comically, angering the others. Fitting his appearance, Kokichi often acts notably child-like, with at least some of it appearing genuine while part of it also could be just his attempt to use his looks to his advantage. He is sometimes shown to have childlike excitement and innocence. He often acts playful and seemingly appears more ignorant than malicious. He is also notably interested in games and often has a strong desire to be a winner and play them seriously while also having fun along with them, with one of his principles being "to have fun" with everything he does. He came up an original theory that enjoying the extreme thrill of cornering yourself with all exits sealed is the definition of fun. Kokichi Ouma can also be rather childish at times, like destroying cities with giant robot dinosaurs, and his Research Lab has a stereotypical dramatic throne of an evil ruler. He himself has openly admitted that as a teenager he is of course immature, and he claims that people should never lose their childish side.

Voice: Here are some of his voice lines from the game, try to get something like this.

https://www.youtube.com/watch?v=0TpbyUusWf8