@theshinygible: Ninja? Seriously? Ninja is a hard warrior to defend as he would die almost instantly. They have no armor, and kill in secrecy. They don't do 1v1. Hell, they don't even do groups. They aren't really known well actually and would be a challenge to research. Sorry to sound like a douche but that's my 2 cents.
I disagree, ninja's are capable of fighting a samurai in real life, so I see no reason why they couldn't be argued for.