You would need some pre-Constantine the Great POD before you can keep Germanic tribes pagan. Once Rome is becoming Christian nation, it is pretty difficult if not impossible stop spreading of Christianity among Germanic tribes.
So keeping Germans as pagans you have wipe Christianity totally off (never exist or Romans are more succesful on persecution) or at least Christianity remain as very small religion. And if you accomplish this, you can write almost whatever you want. This would cause great butterflies.