DEFINITELY Keitaro...who else? Keitaro, 由 far, has the worst luck I've ever seen a manga/anime (more in the manga) character. Yes, I have seen a lot of anime, but Keitaro beats them all. Not just with girls 或者 social behavior (like the average unlucky male character)...just everything, like getting stuck on Islands five million times and trying out for Toudai four times, and so many WORST stuff. His cast is awesome .__.
