God of War Ragnarök

This trophy is earned automatically near the end of the favor Freya’s Missing Peace, which takes place in Vanaheim. As long as you complete the Favor, you will earn the Mardöll sword and the trophy. And once you do, you will then be able to let Freya use whichever sword you wish, switchable at any time.

This favor becomes available once you have helped her break the magic that has bound her to Midgard in the main story quest The Reckoning, and it starts at Freyr’s Camp. You will essentially be visiting several locations along the river (especially if you are also working on other Favors at the same time, namely Mysterious Orb), going back to the place where she was married to Odin. Along the way, you will have to fight a Soul Eater, which is a very similar fight to the one against the Forest Ancient you ran into earlier in the game. Once you have finished the overall set of tasks, gotten the cutscene, and Freya has retrieved the sword, you will go back to the beach to take the boat to leave. As soon as you interact with the boat, you will be attacked by two Dreki. Once you finish them off and interact with the boat again, the trophy should unlock.