According to J.K. Rowling , a telling scene in which Harry uses Cruciatus and Imperius ( unforgivable curses for torture and mind-control ) on Voldemort 's servants shows a side to Harry that is `` flawed and mortal . '' According to J. K. Rowling , telling scenes are when Harry uses Cruciatus Curse and Imperius Curse , unforgivable curses for torture and mind-control , on Voldemort 's servants , and also when he casts Sectumsempra on Draco Malfoy during the bathroom fight in the sixth book . Each time shows a `` flawed and mortal '' side to Harry .