Just some past and present meet to create a fantasy-like universe sort of thing.
Vikings and monks go together like peanut butter and jelly, despite the Vikings’ pillaging of monasteries and making the monks slaves, because a lot of monks also willingly went to Scandinavia to convert the northerners, and in the end the monks won. Even today Scandinavia is a mix of Christianity and Asatru traditions. You just can’t talk about Vikings without mentioning monks.
He's a Viking. He's a monk. They fight crime.