if you can, always have a temple (evileye temple) at the beginning of the path, all Ninja Champions can be downed with 5 meteors except for the last one
on the last one, you must have ghost crytps with maxed freezing at the beginning on the path
and you must only have that crypt because the crypt charges MUST hit the ninja
if you inflict either frozen or fear, you will have enough time to cast 5 meteors and the crypt will deal the other 400 damage (if maxed)
this is luck based unfortunately, if frozen or fear are not inflicted, then you need to be pretty quick casting meteors and building 5 temples and casting the last one for the brilliant badge
you can also use burning temples maxed out, first hit deals SLOW, and ~400 damage on high elevation (with enough red upgrades), that should be enough to kill it.