@Archmage MC
I find her to be interesting, because she isn't all that sadistic, per se. It's more like pushing the limits because she feels like it. She's like a fun-loving teenager with no empathy and godlike magical powers. And, of course, a slight superiority complex.
I mean, sure. Just if Light warns you about giving a bad time, heed her warning. She wont do it unless you REALLY piss her off, but if you don't heed her warning... well... yeah...
The problem is the no empathy part making her come off as a huge dick, or so it seems thats what shes going to be doing. lol