No.
The plural of ninja is ninjae, obviously.
(
Je suis un vagabond is an unfunny, up your own arse middle class knob,
Thu 4 Dec 2008, 12:10,
archived)
Interestingly, the collective noun
is a "Complete Awesomeness" of ninjas.
'ning all.
(
Fishcat Difficult difficult lemon difficult.,
Thu 4 Dec 2008, 12:17,
archived)