You can find Eysa by following the 4th quest of the Dawn of Ragnarok DLC. You will find clues that she has taken some workers to a mylna. The mylna is located in an area from east of Gufathorp. You need to open your map and go to the location on the map with the quest name, The Warlord’s Daughter.
You can go to the point, you can scout the mylna with your eagle bird. Once, you’ve reached the mylna site. You’ll see there is lava there and a statue in the middle of a Muspel princess. You just need to examine the Statue and a cutscene will trigger and you’ve to fight the Eysa.
Once, you examine the statue, The statue will turn into Eysa. You will confront Eysa in a cutscene and right after the cutscene, you’ll fight Eysa.
How to Defeat Eysa
Eysa has a big spear blade, that he does light and heavy attacks with, so you have to block that and dodge. You can attack Eysa with your Sword or your bow, trying to mix your both attacks. You can do your charge jump attack on Eysa as well.
You have to watch out as Eysa does a Fireball grenades attack, You will get a warning on the screen that (Fire Cracking) and you’ll see a red area highlight on the ground so you need to get away and dodge the Fireball grenades in the red highlighted area. After Eysa has taken decent damage, she will disappear in the Lava and small Muspel enemies will come that you can kill and charge your Hurg-rig. After a while, Eysa will come back.
you can now do your jump attacks and sword attacks. When Eysa gets far from you do your bow attack or if you’ve fire arrows do a fire arrow attack on Eysa. Eysa will get down when you’re attacking her with fire arrows you can keep on shooting her with your bow and you can easily defeat Eysa.
A cutscene will trigger after you’ve defeated Eysa and you’ll take her necklace. After, talking about his father and when you’re about to kill her a dwarf will come looking for her, and She will disappear while you look at the dwarf and this was the faceoff with Eysa.