A "Goddess" of butterflies cold and deadly found a man who changed her whole world, evil and dark to Bright and cheerful, the only complications is he is her enemy and behind the murder of her past. (Series?)

he's a king, who's seen as a ruthless killer, he kills cold hearted, he never experienced any love, so he doesn't know how to love, is forced to get married and have a child by his mother's dying wishes and he despises his father for dieing at war against Giants. witches and elves and even dragons and dragon riders now all fight at war with each other, after once long ago teaming against the Giants, shall he find love and a child, Or shall he stay dark and gloomy, like the King he thinks he always will be.