Re: Norse Beastiary - a little help
. . . Iron is a problem. Supernatural beings in later stories (late medieval and onwards) were very sensitive to it. As a gaming trope, it's not very handy, except maybe for flavour. I mean, how many characters don't carry around at least a knife? I advise to ignore this bit.
On the other paw, different critters can be sensitive to different herbs and woods -- like rowan, and whatchamacallit, deadly nightshade. Since each critter has its own specific Achilles heel that the characters have to figure out, that can be a major task if up against some really big monster . . .