Paganism
There are still some pagans in Europe, though they are on the way out. Christianity is relentlessly expanding into pagan areas, but total Christian hegemony in Europe is still far from a sure thing. Lots of the Scandinavians and Slavs remain pagan, though many have also been converted.
The only paganism focused on in FW is Germanic paganism — the worship of Thor, Odin, etc. Your character may be a pagan if you do not wish to play a Christian. Pagans are now only found in the Viking areas (i.e., Scandinavia and its satellites). Paganism is waning for a number of reasons. The organized Christian church is highly effective at missionary work. Viking culture is dying as Viking raiding and war tactics become less effective. Christian Europe is becoming more prosperous as the Dark Ages end, so Scandinavians are willing to convert to have good relations and trade with their neighbors. Finally, the pagan gods, unlike the Christian god, are not jealous of their worshipers — it is no sin for a pagan to worship at a Christian church. As a result, Christianity is infiltrating pagan areas.
Paganism focuses on bravery as its central virtue. The gods are recognized by sacrifice (of animals, food and drink, money, or even people), and most religious ceremonies center around a sacrifice. Paganism does not have some of the puritanical restrictions that Christianity does (e.g., lust and drunkenness are not sins). Unlike Christianity, paganism does not have a central, organized church or a separate clergy (though there are temple attendants). Each free man or woman is capable of leading a religious service, and each temple or household operates on its own, without taking instructions from a central “high priest.”