Details: One of the ten possible challengers you will face as you sit on the Champion's Chair in the Champion's Hall after defeating the Elite Four is Tristan. He was the youngster you first faced one Route 1 when Beginning your journey, and, like yourself, he has come far and is looking to become Champion. He doesn't specialize in any given Pokemon Type, but he is the weakest, level wise, among all the other challengers.
Challenger Tristan - Level 59 Emolga, Level 59 Sharpedo, Level 59 Exeggutor, Level 59 Magmortar, Level 59 Tauros w/Normalium Z