In my D&D game I play with some friends, I appear to have come across a problem. Every time we pass by a tavern our Dragonborn who is a chaotic evil Druid keeps burning them down, is wanted, and kills people for no reason because "it's how his character is played". Frankly, I'm not a big fan of someone going around killing people randomly — and I'm not even joking either. My character is Good aligned and he was also an Ex-Royal Guard, so one of his men breaking laws is something he doesn't like to see.
Now that I have enough reason to kill him, the debriefing!
He's metagaming hard, and I'm not sure if our DM is going to do anything about it (Personally, I don't really like our DM's playstyle. But I give him a chance for he's new.) His character is really strong, so I plan to kill him in his sleep. But because of this, now his character is going to "stay awake until my character goes to sleep, and when I do sleep, my pet wolf is going to watch me during the night". First off, this is reeking metagame. Secondly, even though my character is really nice to his character and he doesn't have any trust issues with my character because of this, he says he's allowed to kill me because "Chaotic Evil can do anything they want no matter what."
Anyhow, I plan to get some meat and fill/coat it with some kind of narcotic to make the wolf pass out. That way I can kill his character off in his sleep.
But since I feel like he's somehow going to maneuver around this, I'd like to know: How can I be sure of killing this character?