Sergei

 is a "Sportlympic" Russian mini-golfer and Pacifica Northwest's trainer.

History
Sergei first appeared alongside his pupil Pacifica at the Putt Hut in "The Golf War." Later that night, he accompanies her in her tournament against Mabel Pines to support her throughout the competition. After the Lilliputtians kidnap Pacifica and attack himself, his charge and their opponents attempt to flee, though he is left behind and is forced to watch the Lilliputtians to perform.

Appearance
Sergei has a tall, rectangular head with long brown hair, small eyes, a square nose and a cleft chin. He has a lanky, albeit athletic, build, and wears a red sweatband, red polo shirt, yellow/gold shorts and black and white tennis-shoes with ankle-high, white socks. He also dons a gold medal, though it is typically covered by his shirt.

Personality
Sergei is a dedicated mini-golfer who takes great pride in his achievements. Likewise, he drives his students toward the same aspirations of greatness. He seems to enjoy musical numbers.