Bagman, Ludovic

From Wikipotter

Ludovic Bagman is head of the Magical Games and Sports department at the Ministry of Magic. He has a taste for gambling, and is often in mix-ups with people he has lost bets with, but has never paid. Prior to becoming head of his department, Ludo was tried for being caught with known Death Eaters. He was not convicted, however, because of his fame as a beater for the Wasps. Ludo is described as looking like a young boy; he has straw-blonde hair and a round face, but has the body of a soiled athlete.

Mr. Bagman's chief role is in Harry Potter and the Goblet of Fire as one of the judges of the Triwizard Tournament. Throughout the competition, Ludo goes against rules, and tries desperately to help Harry. We learn at the end of the book that this is because he placed a bet with some goblins that Harry would win the tournament.