Actually the Vikings had some strange religious beliefs almost like the Klingons on Star Trek. A bizarre one involved their belief that evil spirits roamed the land and the only way you could differentiate them from people was to try and kill it. If you could injure them they were people, if not they were evil spirits. No wonder these guys were considered barbaric and vicious. BTW I am descended from Harald Hardrada, he was killed by King Harold of England in 1066. He sort of set a few historical things in motion, like the full Norman invasion of England after he weakened their army.