No, we never get any explanation for WHY there is a Viking here. Yet here he is, and here he shall stay. He apparently friends with the goat-thing the girls beat up, and it doesn't seem to care that they beat it up. Not that it seems to figure into the movie at all. I think the creators just found a Caliban costume in the theatre department and wanted to throw it in.
Pointless stuff happens.
The barbarian Erlich shows up. Apparently, he and the Viking go Way Back. They decide to keep the girls away from the Evil Sorcerer and almost immediately proceed to fail. The Viking rescues Mira, the younger, and Erlich and Mara get captured and dragged off. Pointless stuff happens.