Really very good.
This is very promising. Good music, an interesting animation style, and rather well storyboarded.
I say work as many of the characters in as possible - you know, as and when you can. It's a series, so there's no harm in that ambition. Personally, I wouldn't want to see the swordsman with the hat and shuriken attached to his sword though. That design was pretty lame, imho. His opponent was cool though.