Yes, there is a manga for Visual Prison. It typically follows the core elements of the Visual Prison franchise while potentially adding new layers and nuances to the story and character development.
The ending of the School Prison manga is quite unexpected. The main characters manage to overcome their challenges, but there are some loose ends that leave you thinking.
The manga and anime of Prison School have some differences. The anime covers a lot of the main storylines from the manga but might leave out some smaller details.
If the protagonist was sick and weak, he could refer to the following novels:
1 " The Salvation Journey of a Sick Teenager "
2. Demonic Patriarch
3." The Prison of the Abyss "
4." Bringing the System to the Other World "
5 "Flower Hunter"
The above recommendations are all comprehensive comics, the main characters are all sick and weak, with unique settings and storylines. I hope you will like them.