were there ninja before the main cast?

whenever a villain/older person in ninjago sees the ninja, they always refer to them as ninja, like they're familiar with the concept. how would they know?? were there ninjas before them?? i know ninjago as a realm is pretty new, only a few hundred years old, don't think there were any mention of historical ninja or whatever submitted by /u/Ok_Boysenberry_6307 [link] [comments]