Why not? Find your self a village and make a viking-raid: BURN;RAPE;PILFER

1. Ninjas are mammals.
2. Ninjas fight ALL the time.
3. The purpose of the ninja is to flip out and kill people.

Ninjas can kill anyone they want! Ninjas cut off heads ALL the time and don't even think twice about it. These guys are so crazy and awesome that they flip out ALL the time. I heard that there was this ninja who was eating at a diner. And when some dude dropped a spoon the ninja killed the whole town.