I suppose they were as "real" to the old Norse as the Greek gods were to the ancient Greek. Which means, present just about everywhere with household shrines, church buildings, regular interpretations of signs and omens etc. Basically, if you died fighting, you went to paradise, where you could fight, wench and drink to your hearts content until ragnarok. Hel (or Helheim to be more correct) by comparison was a dull, grey and listless place. Whether a warrior culture creature a warrior pantheon or or a warrior pantheon created a warrior culture I don't know. But you had to spend as much time as possible with an axe in hand, cleaving skulls if you wanted a decent afterlife.