One who gallavants and/or peruses in the night time. Often wears darker attire to disguise their true identity. Having at least several of the following qualities: stealth, wit, agility, sex appeal, wizardly powers, hispanic origins, and an inner beastliness.
Wow, did you see that shadow? That was probably a night ninja
Dude we should get out of here, this is night ninja territory after 10 pm
I want to be a night ninja for Halloween!