Is viewing and reading images and stories that depict sadistic methods of punishment forbidden, and how can one repent from it, and does Allah forgive those who repent and return, and does reading them during the daytime in Ramadan invalidate the fast?

There is no explicit evidence prohibiting the viewing of images or reading stories of torture. However, jurists have stated that what is forbidden to do is also forbidden to witness. Viewing images and stories of torture may harden the heart and remove mercy, and mercy is essential for attaining Allah's mercy. Watching these things does not invalidate the fast but may diminish its reward. Proper repentance from a sin involves abandoning it, regretting it, and resolving not to return to it.