THE WITCHER 3: WILD HUNT
78 Achievements
When It's Many Against One…
Provoke all Iris von Everec's Nightmares into fighting you at the same time and defeat them.
How to unlock the When It's Many Against One… achievement in THE WITCHER 3: WILD HUNT - Definitive Guide
After you repair the last memory, where you put the bowls in place, you will be transfered to a fireplace-lit hallway, where a specific enemy will attack you. This is the nightmare the achievement is talking about. There are 6 enemies in total and 5 of them are in dormant state. To wake them up, simply attack them with your sword.
As The Mankey pointed out: I had issues trying to strike the dormant guys with a sword. I would miss them several times and be almost dead by the time I got all them hit. Found it was way easier to run way back right away and throw bombs at them. If placed right it should only take 2 to hit them all. Also, keeps you from being right next to them when they wake up.
When all of them are awoken, strike them like a group with your heavy attack, then roll away, prefferably with your shield turned on, as some enemies from the group can do a quick attack, that takes A LOT of health and you want to spare those Swallows to the next part of the fight.
Striking them with your heavy attack has 2 main advantages. You can hit many of them with one swing and they will have approximately the same health when you attack them evenly, so you will have less pain in the second part of the fight. Igni does not work, it only stuns them, I tried.
When you are low on health and there are 4 or more enemies, use food, not Swallow and keep your distance, they do not have any long range attacks at this point of the fight.
They have one lifebar at the top of the screen, but each of them has their own (a couple of 1000s) health. I also used 2 potions, that gave some health back to me when I attacked and took some of their health as they attacked me to make it super-easy.
When you kill 3 of them, their attack pattern will change a bit, so roll heavily and cast a protective shield now and then with some attacking of course. Their attack will wear them down after some time and they will rest on the floor, this is when you must do heavy damage.
I had tried several attempts trying to unlock this achievement and it didn't until I decided to clear my persistent storage under "Disc & Blu-ray>Blu-ray>Persistent Storage".
After clearing, this achievement popped immediately after killing all 6 enemies at once.
**Missable**
This is part of the main quest "Scenes From a Marriage".
After restoring the memories, follow the spirit's instructions and go to the parlor. Check out the note on the table and it will bring you into an arena with a fireplace to face off against a nightmare.
There are 6 nightmares in total, 5 of which are inactive. You will need to wake them up by attacking them with a sign or your weapon. Once all six are active, you will need to defeat them. Use your potions and signs to help you out, and if needed, lower the difficulty as it can be a very difficult fight.
Once all nightmares are defeated, you will be back in the palor and the trophy will unlock.
This achievement is obtainable during the quest entitled "Scenes From a Marriage" and is highly missable.
Once you restore the final memory inside the estate's dining room, meditate to replenish your supplies and make an extra save file. Now adhere to the spirit's advice and proceed into the parlor. Interact with the note on the table and you'll soon find yourself in a large, fireplace-lit arena, facing off against Iris' greatest fear. You'll notice that there's only one nightmare here to fight, as the other five are in a "dormant state."
For the purposes of this achievement, you need to agitate the other five nightmares by casting Igni of them (or striking them). This will "wake them up," forcing you to face off against all six nightmares at once. This can be an incredibly difficulty feat if playing on "Broken Bones" or "Death March!" since the nightmare's are relentless with their whirl-like attack patterns. As a humble recommendation, do not be ashamed to lower the difficulty if you find yourself struggling too much. In terms of the actual fight, it goes without saying that you should prioritize Quen when your stamina allows it, as well as rolling away from your aggressor's attacks and using Thunderbolt Potions, Tawny Owl Potions, and a mixture of both Swallow and White Raffard as well.
Once all the nightmares have been slain, you will be transported back to the parlor and the achievement will unlock. If you failed to provoke the additional five nightmares during the fight, make use of that extra save file you made earlier!
In the Iris estate there will be a final battle with the shadows of Olgerd, which are fears, it will not be possible to provoke all fears at the same time, the main thing is not to kill one of them, while you are trying to distract inactive fears and you can kill them only when they everyone will chase you, the Aard sign (telekinetic strike) helped a lot