Pokémon Certification Test Instructor

The Pokémon League entrance exam instructor is a character of the day who appeared in The Ultimate Test. He was never given any official name.

His job is to oversee the Pokémon League Admissions Exam. He also loans random sets of three Pokémon to the test-takers during the final portion of the test to compete in a battle against him.

He first appeared when Ash, Team Rocket, and Nurse Joy signed up for the Pokémon League Admissions Exam. After signing up, Ash gave him his Pokémon on the counter, save for Pikachu in which he gave to Misty, as he wasn't allowed to have his own Pokémon during the exam. As the exam began, the instructor proctored the students on the first and second part of it. When Jessie was getting disruptive during the second part of the exam as she thought that the questions were hard, the instructor expelled her.

During the third part of the entrance exam, he told Ash and James to pick a set of rental Pokémon for the match while Nurse Joy battled another instructor. After Nurse Joy won, the head instructor battled James. When James sent out two Pokémon at once, he was immediately disqualified. Ash battled him next and went up against his three Eeveelutions. When Team Rocket's Meowth freed the Meowth who was battling Vaporeon from ice, the instructor wanted to catch him, but before he did so, James returned with the instructor's Pokémon. He ordered them to attack the instructor, but the instructor ordered them to turn around, causing the Pokémon to attack Team Rocket instead.

After Team Rocket was defeated, the instructor had to restart the exam because of Team Rocket's interference. He offered Ash to retake it, but Ash declined as he chose to stick to battling in order to get into the Pokémon League.

(Source: Bulbapedia)