Roy Valentine, 35 years old, ambiguously single, known as the capricious mercenary or the god of thunder. As one of the most powerful espers known in Europe, Roy was quite famous, or perhaps the correct word would be infamous.
One of the reasons Roy was famous was obviously how ridiculously powerful he was, but his reputation was strongly related to his personality. Roy was a fickle person who worked for money; he was essentially a mercenary. Roy was infamous because of his capricious nature, which led him to break his contracts relatively often.
From changing his mind and wanting a higher reward than agreed upon to wanting someone's wife or daughter as part of the reward, Roy was known for basically doing whatever he wanted. He refused to honor his contract on more than one occasion because he was no longer in the mood to do so.