The "Vikings" believed in what was a somewhat standard northern European theology, with Odin and Thor, and Loki and Frigg. In their view of the gods, the gods largely ignored humans, more interested in their own affairs--but would intervene on behalf of humans whom they found sufficiently entertaining. Which might be a good thing, or might not be. They also believed that the gods loved chaos, and were bored by order and regularity--so that they were most likely to intervene to upset the apple cart.
They also believed in the Norns, powerful female beings who governed the fates of men and gods. In some versions, the spun and wove, and wove the threads of the lives of gods and men into a single strong thread, from which each individual thread might suddenly be cut, or woven with gold--either destroying the man or god, or granting their wildest desires.
I rather like that view of gods and the cosmos. I believe the most complete version of the Norse mythology is to be found in Snorri Stuleson
, a 13th century Icelandic skald.