Source: https://kakuyomu.jp/works/16818093085137406727
Synopsis
Arazaki Kosuke was hated as a gloomy, loner otaku until middle school.
When Kosuke enters a high school where many of his classmates up to middle school are enrolled, he thinks that his days will just continue to be the same as before anyway, but……
For some reason, he is surrounded by beautiful girls and is in a harem situation.
Apparently, all of Kosuke’s friends (beautiful girls) that he had connection with online and helped had entered the high school.