Masterchief, but he's a popular pick, even though Nintendo and Microsoft have been getting a lottle more buddy buddy. So as my absolute most wanted pick that will never happen, probably the Dovakiin. I can see his attacks now. Basic ines of slicing with a sword. Swapbto a bow for long range. Different shouts to freeze or damage enemies. And finally, FUS RO DA!!!! for the final smash.
Or a Sunwatcher, but I don't think characters from books count.