Possession is a secondary quest in Skellige in The Witcher 3.
Your task is to look for Cerys in Spikeroog and to help Udalryk with his affliction.
Here’s a walkthrough of Possession in The Witcher 3.
Suggested level: 17 and above.
Ask Udalryk where Cerys is
Your first objective is to sail to Spikeroog.
Once you’re in the area, you will see a small town. You can ask the villagers on Cerys.
Talk to Bergthora
Look for Bergthora as she may know where Cerys is.
Talk to her outside the house.
Next, talk to Eiric who is north of the map.
You will find him surrounded by some drowners. Kill the drowners and a cutscene will trigger.
Use delusion to get Eiric to tell where Cerys is.
Go to the abandoned home
Next, head to the abandoned home to look for Cerys.
It’s quite high up. Find the road to climb up.
Look for Cerys
Inside the home, look for Cerys. Use your witcher senses to get clues.
Cerys is lying down in one of the rooms.
There’ll be a cutscene here.
Find the sword Brokvar
You’ll need to look for Brokvar. It’s in the locked cellar.
You need to find the key first inside the home.
Get the key and unlock the cellar hatch. Go to the basement.
You will then see the sword here. Take it and return to Cerys.
Go to Udalryk
Follow Cerys back to town to speak to Udalryk.
Place Brokvar near Aki’s bones
Now, head to the marked area on the map. You have to place the sword near Aki’s bones in an attempt to lift the curse.
Aki’s bones is at the seabed. Watch out for the Sirens as well. You can kill them using a crossbow.
Go to the bones and examine it to place the sword.
Nearby, there’s also a chest that you can loot which is part of the quest Not Only Eagles Dare. It’s locked and the key is on the small isle just nearby.
Return to Udaryk
Go back to Udaryk when you’re done. You’ll learn that he poked his eye and Geralt is certain that a hym is possessing him, not his dead brother.
Witchers’ way vs tricking the hym
You’ll have to decide if you want to use the witchers’ way or try tricking the hym.
The outcome is probably the same. The witchers’ way is to basically get Udalryk to go back to the abandoned home and wait for the hym to spawn.
Then, you just have to kill the hym.
Tricking the hym is a much more elaborate way.
Search the abandoned home
Cerys believes you should try tricking the hym. Head to the abandoned home first.
Examine the oven and other clues in the house to get a way to trick the hym.
There’s also a baby crib.
Talk to Cerys
Once you’re done examining, talk to Cerys.
During the conversation, if you choose “No way”, you’ll do it the witchers’ way.
If you choose “I trust you”, then it’s up to Cerys to trick the hym.
Tell Udalryk about the hym
We chose to just kill the hym. Talk to Udalryk again.
Place torches in the home
Once you’ve convinced Udalryk to stay in the abandoned home, you need to place torches.
There are 4 in total.
The next step is to light the torches when you’re ready.
Kill the hym
The hym will appear after the torches are lit. Try to kill it.
After some time, it will run away.
You’ll need to calm Udalryk using Axii first.
The hym will appear again. Fight it until it retreats.
Go to the cellar to finish the hym
Head down to the cellar to kill the hym.
The quest ends here after the cutscenes.