Actually katana translates into english as "sword", so yes the ninja did actually use katanas. As for the black garb, I seriously doubt they went on assassination missions dressed in white.

Katanas were wielded by Samurai. Ninja were in fact spies and assassins, rather than warriors. They probably never wore the black garb commonly though of today, as that derives from a Japanese theatre where stagehands wore it, and ninjas were mixed in among the stage hands.

Yeah, but Naruto isn't really a good source for an explanatory essay.

Also, it's not really the reader's responsibility to know what iaido, kendo, and shakendo are, because as the ** writer you're supposed to explain it. Which is, y'know, what you're supposed to do in an explanatory essay. Instead of, y'know, relying on the reader knowing everything you're talking about. In which case, y'know, they wouldn't need to read the essay anyway.

Oh, and by the way, it's "reconnaissance."

A very nice essay. As you said, sometimes ninjas would spread myths about themselves so that they would appear more powerful.

I believe in "ki" to some extent in that I think there is a spiritual part of you separate from your body. I've seen and done experiments where one can isolate themselves from pain for example.