Wes is the main character in Pokemon Colosseum. He is a silent protagonist and as such not much is revealed about his personal life during the game. It is assumed while talking to characters that know Wes he may of been a thief prior to the game which is quite the opposite of the current Wes whose main goal is to put an end to the theft of Pokemon through the Orre region.
Wes was for an unknown amount of time part of Team Snagem, a group of thugs who had escalated to stealing Pokemon from trainers over the years. In the opening of the game Wes is seen destroying one of their hideouts and stealing a contraption called the Snag Machine, which gives the wearer the ability to steal Pokemon from other trainers. Being a force of good Wes never abuses this and only uses it to steal Shadow Pokemon from Team Snagem, which are Pokemon who had already been stolen from their original trainers.
Wes is joined by a girl named Rui who he had rescued from her kidnappers at the start of Colosseum, and his two favorite Pokemon, Espeon and Umbreon. Together they work together to unravel the truth behind Team Snagem and put an end to the production of Shadow Pokemon.
Pokemon XD: Gale of Darkness
Wes is absent from the sequel to Colosseum, Pokemon XD: Gale of Darkness. He is mentioned in passing during the game but his whereabouts are unknown after the events of Colosseum.