Here is the full list of all 20 The Frostrune achievements.
It is better to never ask for help, than to ask one time to many
Thou shalt pass all doors
Welcome to Ullrs realm
Hymir gives the greatest catch
The dwarf is the master of rock
Andrimner is he who makes food in Valhall
No secret was hidden from Heid
The wisest thing to do is to make a friend
This is no place for the living
You are no friend of beavers!!
Menglöðs beauty would melt all ice
When friends are together they are the strongest
Baby, it’s time to dance!
The world is big when you can see it all
When Ragnarok is over, the survivors will gather at Iðavöllr
The wisest squirrel in the tree
Well, hello sir!
Happy is she who plays with fire
You don’t know until you try
Sleipnr was the fastest horse of them all