ninja
Just wanted to add to Ryoko-chan's analysis for Rue:
Another part of Rue's love for Mytho is that for quite awhile, thanks to her "dad", she thought that Mytho was the only person who could love her. I really don't remember which episode it was, but sometime in the second season, Rue is told by the Raven that the only other person in the world who could love her, besides himself, was Mytho, because he loved everything. The concept really isn't true, but since Rue was told that for so long, naturally she would believe it. I think that belief, along with jealousy, was the reason that Rue/Kreahe was so desperate for Mytho to be hers- because she thought that no one else would love her.
I'm not sure how much that had to do with 'good being tainted with evil'... but the topic is Second Season Discussion... sweatdrop whee