Kazuya Kinoshita

The protagonist of the series. He is enrolled in the Business Administration Department at Nerima University. At the start of the series, he is a first-year university student who took a gap year, aged 20. In the drama version, he is a 20-year-old second-year student. His birthday is June 1st. He lives in room 203 of Royal Hills Nerima.

Initially, he has an indecisive personality and sometimes lies to those around him to indulge in a sense of superiority, which often leads to trouble. However, he is aware of the inconvenience he causes and tries to protect others' secrets and important things, even at his own expense.

His first girlfriend was Mami, but she broke up with him after just one month. Out of loneliness, he hires a rental girlfriend, where he first meets Chizuru Mizuhara. Subsequently, he introduces Chizuru as his girlfriend in front of his family and friends, starting a fake romantic relationship.

At first, he wished to reconcile with his ex-girlfriend Mami, but after saving Chizuru when she fell from a ferry at the Shimoda sea, he gradually starts to become conscious of her.

While continuing his rental relationship with Chizuru, his friend Kuribayashi rents Ruka, leading to a double date. This results in Ruka developing feelings for him, and with Chizuru's encouragement, she becomes his temporary girlfriend.

After hearing from Chizuru that her grandmother Sayuri doesn't have much time left, he starts a crowdfunding campaign to produce a starring film, successfully raising funds. They begin film production and hold a screening in the hospital room just before her passing. Kazuya attempts to confess to Sayuri that Chizuru is not his real girlfriend, but Chizuru stops him.

After Sayuri's death, he goes on a comforting date with Chizuru, becoming closer, but their rental relationship continues.

Following a suggestion from Kazuya's grandmother Kazu, they go on a family trip to Hawaiians with Chizuru, Ruka, Kibe, and Kuribayashi. They meet up with Mami there, and due to Mami's actions, the family discovers that Chizuru is a rental girlfriend.

He keeps a lungfish (voiced by Saika Kitamori).