If for some reason you're looking for very dark dramas with revenge plots, I believe King of Pigs and A Christmas Carol have it. These two are similar as they deal with: hardcore bullying, s*xual assault, and other violent themes.
Aside from the aforementioned, both contain a revenge story. Whilst Kyung-min avenges his lost childhood in the King of Pigs, Il-Woo attempts to try and fight for his brother's death in A Christmas Carol.
Both have characters with mental disabilities, though they differ.
I believe these two films should have warnings of their own as they're both mentally torturing to watch, and are embedded in your head forever. I highly advise that you take precautions and only watch either one of them if you're truly mentally capable, as I had nightmares after finishing King of Pigs.
Aside from the aforementioned, both contain a revenge story. Whilst Kyung-min avenges his lost childhood in the King of Pigs, Il-Woo attempts to try and fight for his brother's death in A Christmas Carol.
Both have characters with mental disabilities, though they differ.
I believe these two films should have warnings of their own as they're both mentally torturing to watch, and are embedded in your head forever. I highly advise that you take precautions and only watch either one of them if you're truly mentally capable, as I had nightmares after finishing King of Pigs.
Two friends in the past were victims of serious school bulling. One could not resist his trauma, and becomes a serial killer, walking in the path of revenge. Another one tries his best to overcome the trauma and becomes a police detective. He now faces tragic fate to risk his life to capture the serial killer.