I started playing DnD recently and I finally understood what these were. I was looking at some of them already on DA and I didn't think that they aligned right. So here's my take.
I wouldn't quite say Light is Chaotic. He seems to be doing things for some cause, not wanton violence. Ryuk is just doing things for shits and giggles though.
I think L is more of a Chaotic Good, but what do I know
I was debating with him. In the game, chaotic good is usually a selfish person who does good and neutral good is someone who does good just to do it. I figured L fit neutral more than chaotic.