VIDEO & TEXT GUIDE
LEVEL 29 Recommended.
Friend or Foe starts in the Skellige Isles. The place you want to head to is called Rannvig if you have managed to find the maps sold by merchants you should have unlocked this fast travel point by using them, there are 4 maps in total so keep an eye out for them or do a quick google if you are yet to find them to find out who sells them. There are several merchants that sell them as i had all 4 and still found merchants selling them afterwards.
Once in Rannvig head to the notice board and pick up the Missing Son contract, this is the contract needed for this trophy. Once picked up from the notice board and the Missing Son Quest selected from the Contracts head to the location on the map but just before you get there you will want to apply Relict oil or the enhanced version if you have it to your silver sword, you will also want to select the SAMUM bomb and Devils Puffball bomb or again an enhanced version if you have them. Make sure you do this before the fight because it will not allow you to once the fight has started. You should be able to see your foe and back off to be able to ready your self without him attacking.
It is a Fiend you are fighing if you wish to check up the Beastary about it.
Pick a Decoction that suits your battle style also. The Fiend decoction doesn't really do anything to help with the battle it just allows you to carry more items past your weight limit.
2 good potions are Thunderbolt and Swallow again you can get enhanced/superior versions of these.
Head in to the building area that is almost like an arena and fight him for the first time, don't worry when the screen goes black when you beat him this is just their way of making him vanish to his lair which you need to find using your witcher senses. Make sure to grab the 4 loot parcels at the back corner for some nice diagrams etc then head off using your senses to see which way he ran.
Before you do this would be a good time to meditate so you can get your health back and fill your bombs and potions up again ready for the next battle.
Remember though this will mean you will need to apply oils again and use decoctions as meditation can clear the use of them so just check on that before you go further.
Once you have done this you are ready so keep using your witcher sense until you find him and as soon as you do use your QUEN sign and then use your bombs and potions and get in there and hit him hard. When your QUEN has been blown get out the way and apply it again. Once the fight is over remember to loot him and then use your senses in the lair to find the dead son.
Once you have found him head back to Odhen who you will find in Rannvaig where you got the contract.
If you need help finding anything just check the video out. Once you speak to Odhen you will get the trophy.
Good luck and happy gaming