Realm of Darkness

The Film starts late in the 17th Century with a group of Scottish Clansmen and specially trained monks fighting a mixed batch of demons including Satan and his son Terrence to stop them ruling the World. Satan has an agreement with God, that every millennium, he can take human form and impregnate a female of his choice, when the baby reaches its 18th birthday it gets the same powers as Satan and they join forces to rule the world and turn it into their evil kingdom, allowing Satan freedom from Hell. However every millennium the monks have one individual gifted with speed and expert fighting skills, whose job it is to prevent Satan's sibling reaching their 18th Birthday..