Ninja mode is supposed to be used when you are doing repetitive, remedial work like changing categories on 200 pages, [be]cause you think "author" is better than "authors", or when you've created a new page that has 100 potential pages linking to it, adn  all you will be doing is adding brackets to the word "the" 300 times. There really is no reason for it for any day to day editing.
A list of ninjas for hire can be found here.
To request ninja, please add a request to here.
The userbox at right does not appear to actually have anything to do with this group. But if ninja-powered users wanna add it, that's cool.
Dispelling unfounded rumors
There is no such thing as a "pirate" user group.