One of, if not the, vilest villains in all of the MCU was Kilgrave, a sadistic rapist with the ability to make anyone do what he commanded with his words. Even more than forcing people to kill themselves (or others), this purple-clad monster, born Kevin Thompson, enjoyed keeping women as sex slaves. The object of his deepest fixation was Jessica Jones, whom he forced to be his personal servant for months. This was some of the darkest territory ever tackled by the MCU (while on Netflix) and it was enough to rocket Kilgrave up toward the worst of the worst.
10/10