From Johou Battle:

A frenchman who is defined by his honor and his pride as a Stand user. On a quest to avenge his sister's death, he joins up with the crusaders after they saved him from a life of DIO's brainwashing. Polnareff enjoys the art of the fight, taking so much pride in the abilities of his Stand, Silver Chariot, that he will happily explain them to his more honorable opponents, even handicapping himself at first to see what his opponent is truly capable of before taking them down! While he may be blinded by his pride, he will still go all out on more dishonorable enemies without hesitation, even to a fault!

You wouldn't think he's like that if you weren't fighting him: His other hobbies involve oogling the ladies, cracking jokes, leaning back, and taking care of his tower of hair!