Yuuta

Daniel is a character of the day who appeared in A Marathon Rivalry!. He is a boy with glasses who wears a lab-coat and always carries a laptop, which he uses to analyze his Pokémon's condition.

Daniel lives in Camellia Town and trains a Snorlax as his main Pokémon. Daniel believes that the best way to train his Pokémon is a "scientific" approach; therefore, he uses high-tech machines to train them. Some of these machines were seen when Daniel demonstrated his training style to Ash and his friends in his training lab. He also believes that the Pokéathlon better compares two Trainers' levels of synchronicity with their Pokémon than does a Pokémon battle.

Daniel eventually won the Sinnoh Pokéathlon, which qualified him for the Johto competition.

(Source: Bulbapedia)