Here is the full list of all 14 Fimbul (EU) trophies - there are 3 silver, 10 gold and 1 platinum.
All done!
Kill Knut.
Spare Knut.
Kill all Trolls.
Spare all Trolls.
Bring at least one Troll to the Jotun fight.
Go through the gate to Jotunheim.
See your mother die.
Escape the cave.
Kill a half jotun.
Bring warbanner to Thora.
Become a mountain.
Become a Jotun.
Go back to the farm as a kid.