Board Thread:General Discussion/@comment-4962906-20151111090025/@comment-4975807-20151112052502

I think it was several contributing factors that made her skin turn green. First, she drank from the Holy Grail, and gained both magic and immortality, but she used magic to kill someone, which I guess, in the magical sense, it's considered bad because she was doing it out of hatred and vengeance. The fact her skin turned green was perhaps the magic's way of reacting to how she used it. The enchanted heart thing is similar in a sense because a person's heart can be become blackened by doing bad acts, except it's the heart that turns dark, rather than the outside physical appearance of the person.