Nice!
Looks pretty neat!
A pupil would be nice to have, he looks kinda spooky as he's now.
The hands seems too small.
Those large red 'plates' looks kinda useless and unconvienent.....it makes the Ninja look less flexible/limber and less fast somehow, it just would hinder the ninja's movement.
About the feets (and perhaps other body parts, details etc.), check the picture below (it's not mine).
Hopefully you and your friend will create the comic soon, I'd like to see it!
Keep up the good work eh!