Finished reading this on mangaowl. 4.5/5 stars
My only issue with this manga was that the mc was 15 years old and the alpha was probably a young adult, based on the context and dialogue since I don't think they actually stated his age. Not that much of an age gap probably, but still, an adult having sex with a minor - it's kind of a turn-off, even if it is fiction. But nonetheless the mc was good and Kaisei was hot and became slightly better at the end, so that made things slightly decent. He certainly wasn't the most likeable character though, even after his slight character development.
Secret Note