Whether he could kill them depends on whether they have some conceptual immortality hax that puts them back together no matter what, or whether they can just be vaporised to end them. Musashi was only chopping off heads and limbs, which they put back on. Arondight beamu would straight-up remove them from the playing field.
That said, there's a reason one of the most asked for matches in this thread is Lancelot/Kojiro. Kojiro's so good he breaks reality, and Lancelot's shtick is that he's the (magically proven) greatest knight of his age.