In a close-quarters battle, Kain would definitely be the victor. He not only has superb endurance above that of any human or half-human, he can block and dodge. No manner of blade could destroy the Soul Reaver. In addition, if Dante struck, Kain could turn to Mist for a short time and dodge.
Well, I hate doing these things by myself. Once someone posts a [i]real[/] battle strategy, I can have an idea of what to have Kain to do.