Skullduggery (1983 film)

Skullduggery aka Warlock, aka Blood Puzzle is a 1983 Canadian horror film directed by Ota Richter.

Increasingly Adam is unable to determine the difference between fantasy and reality and believes that, as a warlock, he is on a quest to kill various people. As the bodies pile up, the local police are baffled and no one suspects that Adam is a deranged serial killer being commanded to kill by the devil.After playing the role playing game with instructions to kill all the members of the Apostles of Hell before they kill him, Adam attends a costume party hosted by a man named Dr. Evil, who wants Adam to join his cult and also kill most of the female and male party guests. When the police figure out that Adam is the killer, they corner and shoot him in a factory, but his body disappears and leaving a puppet in its place. ........

Source: Wikipedia