Sounds like you could benefit a lot from reading what C.S. Lewis has to say about myths. He touches on it in "Surprised by Joy" and I believe the essay he wrote has "Myth" in the title. (Sorry, that wasn't particularly helpful, was it?)
Anyways, my personal take is there is no such thing as a christian anything, besides people and the Bible. A story is a story, a myth a myth. Now they can most definitely hold legitimate God-ordained truths in them, Lewis argued that the early Norse, Celtic, and other Ancient myths did. In the sense we are talking in, the battle between Light and Darkness could be said to have originated before the Christian Myth (aka, the only True Myth. Please read more Lewis. >_<) since recorded and oral tradition place these myths long before the recorded Bible. The take away is that truth is truth. Just because Balder* did something God would command, or King Arthur said something Jesus would too, does not make them Christian, but doesn't mean the act wasn't righteous or the statement false.
To conclude, I would not say that RWBY is a Christian anime, but it most certainly heralds qualities and concepts lauded by christian ethic and displayed throughout history as noble. And I think God honors what honors His truth, according to the capacity to which it honored it.
...yeah, skreyola said it better. >_<
oops, I left an asterisk hanging... So: *I haven't actually read the myth about Balder. CS Lewis mentions it by name, and then there's some Balder Knights in Dark Souls. SO if the example doesn't hold up... sorry. >_<
Last edited by Rusty Claymore
on Mon Dec 21, 2015 12:17 pm, edited 1 time in total.