Well what started out as a random drawing of a MLP turned in to Kai from Lego Ninjago, Some of you may be saying why isn’t he red or something, for some reason A lot of people when they draw the ninjas as ponies they automatically make their coat colors the same as their ninja uniforms and give them their elemental symbol as a cutie mark.
 
Although this makes them more recognizable, This makes little sense to me, because the Ninja all started their ninja training when they were ADULTS … or late teens IDK (minus Lloyd of course who was a kid) meaning they would already have their cutie mark at this point . And so they would have already found their special talent .and until they met Wu they didn’t even know they had elemental powers so it would make no since for them to have a cutie mark representing it when they don’t even know they have one. So this is why Kai has a sword , because like his father he is a blacksmith and crafts them (and is also really good at wielding one).
 
And about the coat color unlike a lot of other things that people turn in to Ponies like Transformers who’s colors are part of their armor (basically skin) and can not be removed (like clothing) so its naturally what color they are (but can be change … but now going over this right now) and so would be the same or similar color in pony form.
 
But the Ninjas are Lego (technically human but whatever) so it would be odd for say Kia to be born bright red only to coincidentally be the Red Ninja when he gets older (and do not say “its because his father was also the master of fire”) although that’s true, neither of his parents were ninja (at least as far as I know do not spoil anything) and it would also look really weird for him to be wearing a bright red Ninja suite when his coat is already bright red. so apart from Zane all the ninja will be either a (MUCH) paler shade of their color or just a completely different color altogether.
 
Sorry for the Mini Rant but to me this makes a little more sense to me
 
Video Link -> www.youtube.com/watch?v=2gyXtf…
 
IF there is a Ninja or other Ninjago characters you want to see as a pony please comment below (just no one from season 6, as I haven’t seen it yet )
 
Ninjago belongs to Lego  
My Little Pony belongs to Hasbro