The deciding outcome on a Pirate v. Ninja fight is numbers. But not like you might think. Let me explain..
The number of pirates to number of ninjas is crucial. The higher number of pirates to ninjas, the better chance the ninja has of winning. Why? Because it is science, science I tell you!
Yet, on the flip side, when number of pirates to ninjas comes closer to becoming equal, pirates will have the upper ground.
Examples) 100P v 1N = 0P, 1N 1P v 1N = 1P, 0N
So in the end it relies on the number on each side.