All android systems warn you that applications outside of Google play can be harmful. The file contains nothing wrong, however you can always go to VirusTotal to examine it.
Remember that he is no longer studying, Aiko told him to go to school for the first time dressed as a girl, he could have lied about his age to enter there to study, also two years apart is not much if you have repeated a course
The pills are not known who developed them, the drink is not magical, but they call it that because of the immediate effect it has.
In my country, high school is up to 18 years old, at no time is it discussed where the story takes place, so it is possible that the MC continues to be in contact with people who continue to go to that school
