Monthly Obscure Trope Series — Conservation of Ninjitsu

“In any martial arts fight, there is only a finite amount of ninjutsu available to each side in a given encounter. As a result, one Ninja is a deadly threat, but an army of them are cannon fodder.”

From the TvTropes page.

This is one of those tropes that I think is as well known and wide-spread as the Training Montage, but most people probably didn’t realize had a name.

You see the Conservation of Ninjitsu all the time in books and movies. The hero wades through countless mooks (henchme...