Pfft, ninjas had smoke bombs, shuriken, ground spikes, taijutsu (i'm NOT talking of that naruto stuff, although I do enjoy reading the manga frquently), and the nine steps of the dragon (walking in silence, actual ninjitsu). Knight has armor? Throw 8-tipped shuriken in his eyes. Knight is fully protected from shuriken? follow them back home after they've finished their jobs. Knights got horses? One of the 14 ninja arts was horseback riding. Ninja got no horse? Ground spikes will make them go zoller wallers. Ceing charged by knights? Throw shuriken at horses, throw footspikes on the ground f or good measure, use smoke bomb, run like hell throwing a smoke bomb back wards again, take a right (people always turn left), engage in the art of hiding like a quail/raccoon (Can't remember which), become part of scenary and use meditative breathing to hekp not mmove under draped black robe, and wait. Ultimate pwnage right there.
with pirates, they'll just hit the knights when they're both on ships with cannons. On ground, pirates are relatively fucked, so it goes in order of this:
1. Ninjas
2. Wizards
3. robots
4. Knights
5. Pirates
6. pimps.
.....
Knights are cool th ough. Combine with robots, and you are almost at the level of wizards..