People like that don't need a reason apart from "because I can". They have a nightmare and try to make it happen.
Terry PratchettWinners never talk about glorious victories. Thats because they're the ones who see what the battle field looks like afterwards. Its only the losers who have glorious victories.
Terry PratchettGranny Weatherwax was not a good loser. From her point of view, losing was something that happened to other people.
Terry PratchettHe'd always known that the world was an interesting place, and his imagination had peopled it with pirates and bandits and spies and astronauts and similar. But he'd also had a nagging suspicion that, when you seriously got right down to it, they were all just things in books and didn't properly exist anymore.
Terry Pratchett