Haruhiko Usumizawa teaches Japanese to Class 1-A at Y-Academy, overseeing students like Jinpei Jiba, Mataro Tamada, and Sandayu Koma while managing student housing. He has white skin, wears glasses and a black toupee, and dresses in a brown coat over a beige sweater, white collared shirt, green striped tie, grey pants, and black shoes.

He induces Onryo transformations in others by infusing strands of his hair with magical breath and directing them at targets, an ability granted by energy transferred from Nayu Kuruhoshi. Initially acting under alien coercion, he transforms individuals like Suruzo Oita and Kyodai Salaryman Miyazawa-san into hostile entities such as O Eater and Cyclops.

Haruhiko is the reincarnation of the yo-kai Whisper. Though he serves as an antagonist alongside Nayu under alien orders, leveraging his strong spiritual energy, his true motive is to strengthen the YSP Club by creating challenges. In a key moment, he gives Jinpei his Y Medal, enabling Jinpei to transform into "OK Haruhiko," a translucent blue entity with a ghostly tail instead of legs.

He redeems himself by freeing Nayu from robotic replacement and joining the YSP Club to counter extraterrestrial threats. His laptop resembles Whisper's Yo-kai Pad, and his favorite food is lightly grilled Uguisu bread.