This guy doesn't just have a license to kill: he gives them out. Lieutenant General Corman's the general who orders Willard to kill Kurtz. While we're not entirely sure whether Corman wants to kill Kurtz because Kurtz is too brutal, or just because Kurtz has broken the chain of command (which is what Kurtz thinks), Corman provides some perceptive insights into Kurtz's psyche. He gives Willard this somewhat melodramatic speech:
CORMAN: Well, you see, Willard, in this war, things get confused out there. Power, ideals, the old morality, and practical military necessity. But out there with these natives, it must be a temptation to be God. Because there's a conflict in every human heart, between the rational and irrational, between good and evil. And good does not always triumph. Sometimes, the dark side overcomes what Lincoln called the better angels of our nature.
This guy must have been talking to Yoda: "If once you start down the dark path, forever will it dominate your destiny. Consume you, it will."