
Basically Deniz's attitude towards others is that they have to be "beautiful" enough to live in this world. In his mind Na Kobeta is hideous, therefore he believes he shouldn't be in this world, which pisses off Na Kobeta since his comment is trivial.
Deniz is basically bootleg Vega, since Vega also has an obsession with physical beauty. However Deniz isn't truly evil. In fact, he's neutral. He's literally at the point where he's willing to do anything for his love regardless of right or wrong. Sometimes he says things which he doesn't mean, as his sense of judgement is clouded, therefore making him act upon impulse.
He's actually participating in the tournament to gain Destiny's power and break his love free out of a coma. She got involved in an accident on her way to get some supplies for his crop business. As soon as he was informed by the local hospital.. he felt responsible for not being there for her at that moment, since he runs the ricefield seen in his stage and makes profit from his land as he grows crops on a regular basis. Hellbent on getting his love back in his life, and obtaining the Ox Spirit" from his grandfather (who passed away prior to the events of the game),
Na Kobeta is a broken man who's youngest daughter died in a savage ambush upon his village located in the Democratic Republic of Congo, where he lives with his wife and children. Destiny appears before him and tells him that she's coming for him and the rest of his family soon. She also tells him to stay away from the Phoenix King. This confuses him as he doesn't know what's so special about this so called Phoenix King.
Alarmed by Destiny's threat, he is guided by the Spirit of the Serpent on a journey all the way to the United Kingdom, and meets Rubel at the airport. Upon meeting Rubel, he is given a chance to seek revenge for his lost daughter by entering the Humanity Climax Tournament. He joins him in the fight to stop Destiny as a force of vengeance.