BioYas is the the leader of the proposed Yas Gym who contested with the Kaz Gym to be the main gym in Dark City. He proposed to his bodyguards that they should crush the cretins at the Yas Gym into pieces before the inspector from the Pokémon League arrived so that they would be the only gym petitioning to be an official league gym.
His attitude changed when he was defeated by a clever plan by Ash and his friends. Nurse Joy. who was the inspector. had been watching in disguise the entire time and she told him that people who only see Pokémon as something to settle conflicts with can't run an official Pokémon League Gym. He then said he wanted to change and she told him to listen to what Ash had to say as she thought he was more qualified to tell them what they needed to do. He told them to fix the town, have a change of heart and start walking the path of a Pokémon Trainer which he seemed to have started do just as they were leaving the city.