every movie and music video I have seen them in, they totally get their asses kicked by the heroes. They appear, start swinging swords, climbing walls, do jumping backflips, landing on tree branches. They put on a show, act like they are hot shit, then one by one get whooped by two or three guys (or even girls). Sometimes, when a ninja knows its beat, the mask will come off to reveal a hot female, who then gets porked by one of the heroes.
They should use their strength in numbers to dogpile on the heroes instead of wasting energy flipping around!