Manga Kimi Wa Midara Na Boku No Joou

When they were still young, Saito and Kavana Subaru were close friends. But since Subaru came from a wealthy family, she was sent to high school, while Saito had to be content with ordinary education. But after excruciating studies for many years, he was finally accepted as a freshman in high school through a scholarship program that only a few students receive.
But what Saito considered a touching reunion turned out to be terrible. Subaru grew up beautiful and was the most popular person in school, as she was kind to everyone except Saito, whom she seemed to despise.
Almost regretting his decision to come to school, Saito would like their dormitory rooms to somehow connect with each other.
Magically, since it turns out that Subaru wanted the same thing, their desire comes true, but in return Subaru loses his temper for one hour a day.
At this time, her erotic desire for Saito, which she can usually hide, spills out, and her true intentions are revealed. He wants to take this only chance in life, but it could jeopardize their relationship for the other 23 hours.