Until the Princely Childhood Friend Becomes a Sow

he protagonist, Mamoru Sato, is an utterly ordinary student without any notable characteristics. His grades are average, and his athletic abilities are typical.
He does not have any exceptional talents nor does he excel particularly at anything.
In contrast, his childhood friend, Sei Asahi, is a paragon of both academic and athletic prowess. Coupled with her handsome face that rivals that of any man, she has a massive popularity at school despite being a woman, earning her the title of the “prince.” The nearly invisible mob character protagonist and the popular childhood friend heroine. At first glance, they seemed unlikely to interact much, but in reality, they got along very well and even commuted to school together every day. nMamoru and Sei walked side by side, enjoying casual conversations as they headed to school again today. “I’m happy enough as it is, but someday I hope I can confess my feelings to her…” The protagonist walked happily with such thoughts, but the arrival of a certain transfer student would quietly bring an end to their peaceful days.