Pagan societies don't condemn war so it's not a contradiction with their religion. Think of Greece and Rome and Mars. Or look at the wars of the Aztecs to get prisioners to sacrfice to Qu--.
Or the Vikings. Or the Celts.
Pagan societies were very warlike.
By the way, the last war of religion between Christians was in the 1940s, between Catholic Croatians and Orthodox Serbs. It exterminated more than half a million.