Well, I've put this long time ago on Kotal Kahn's thread, but this is interesting.
Considering his variations and his appearance, he is totally based or in tribute to Huitzilopochtli, god of war, blood and specially sun on aztec pantheon.
He could also be the god himself, but, as we already seen, he paints his skin.That proves nothing, but gives a more "human" aspect.
Ferra looks indigenous, has body paitings and, most interesting, has the term SILVER HAIRED WOLF QUEEN written on her headpiece.
Kotal Kahn has been said to want to preserve her race, showing a connection. Also, it always seemes to me that the Jungle Stage was someplace VERY LIKELY mesoamerican forests, even with an olmeca head and a waterfall, not even mentioning the consitency of the leafs.
It's kinda evident that Nightwolf is not becoming the only character of indigenous culture, though he is a descendant of the cultures that survived (the best term...) on North America.
Anyway, Aztecs also had origins on closer locations to what is US today, though they settled on Tenochtitlan (City of Mexico).
I find this very interesting. Specially because Nightwolf recognized Raiden as Haoka, so there is a connection between cultures, that's why Kotal Kahn may also be the Sun God for real.