Is the special ability in warfare really unique or is it just high morale? Morale is a key element in warfare, and it may coexist with this special ability. Some call it impetuousness or savage courage. Knights seem to have a similar quality, suggesting it could be a morale bonus.
This show picks up where Dan's Thor's Angels show left off. In the early Middle Ages Pagan Germanic-language speakers like the Vikings are a dying breed. Many of their contemporaries wish they'd die faster.