1) Make him fall in love 2) Make him fall in love with an already mated character 3) Make him crazy/join Kili 4) Make him under the influence of Kili, to the point that, even should Kili die, he will still have multiple-personality-disorder. (What I'm doing)
Will this help?
This guy is so evil you could put him in between two slices of bread and call him an evil sandwich.
If you don't know it's impossible it's easier to do. And because nobody's done it before, they haven't made up rules to stop anyone doing that again, yet. — Neil Gaiman