The Witcher 2: Assassins of Kings
50 Achievements
1,000
50-60h
Friend of Trolls
Spare all trolls in the game. Details for this achievement will be revealed once unlocked
15
How to unlock the Friend of Trolls achievement in The Witcher 2: Assassins of Kings - Definitive Guide
If finishing Chapter 1 on Roche's path, things play out a little differently -- at least, they did for me.
The Chapter 1 troll is the same. You have to do the quest involving "helping" the troll. Just ignoring him entirely won't get you the achievement.
In chapter 2, there is a wild troll in the ravines which you can find early on. I didn't kill it (just avoided it), but I've heard that it doesn't matter.
The two main trolls, I encountered in reverse order. Late in Chapter 2, in The Siege of Vergen, you'll be travelling the ravines to get back to Vergen. I encountered the female troll first. Just choose conversation options that are non-confrontational. Then, you'll go past the quarry (can't miss it -- it's a huge hole with spiraling paths leading down). Go up and around to the left of it, and you'll find the male troll. He's under attack, so help dispatch the attackers.
I initially told him that his wife might have encountered some soldiers. He decided to go to Vergen to join the battle (although he didn't get far), and even though I didn't kill him, I didn't get the achievement. I reloaded a save prior to the female troll, talked to her again, got to the male troll, and this time told him his wife was okay. He heads off to find her, and the achievement unlocked almost right away upon ending the conversation.
Hope that helps, for people on Roche's path.
The first is in ch. 1, under the bridge, when you get to him you have the option of killing him or helping him, just dont kill him and you're good.
The other two trolls are in ch. 2. You meet a male troll who tells you to find his wife. She is being attacked by mercenaries, and you need to put a stop to it and reunite them to get the achievement.
Basically, just don't kill any trolls you find and if you do, reload you're save and choose different options!
There are a total of three trolls throughout the game. For this achievement (I'd recommend doing this on Dark difficulty, just to avoid any frustration), you are going to need to not kill any of them. Completely ignoring them will not net you the achievement.
Chapter I
There is one troll in this chapter. First off, you can't just ignore him and get the achievement. You must participate in his side quest to count for the achievement. You can always find it by the ruined bridge, but just to make it easier, take the quest "Troll Trouble" on the noticeboard outside of the inn. Upon going to the troll, you will fight it a little bit, but the fight will stop when the troll's health is about halfway down. He will tell you that if you help him find out what happened to his wife, then you will be able to pass. Agree to this, and it will start a subplot about finding the wife. Talk with Zoltan and Sile at the inn in Flotsam, and you will then be tasked with searching Sendler's house (close to where Cedric is located). He will tell you he was sold the head of the she-troll to him by a bandit named Dmitri. He will tell you that the bandit is located at the cemetery which is right by his house. Kill the bandits and then return to the troll telling him about his wife's fate. He will let you through after that.
Chapter II
Towards the end of the chapter (regardless of whose side you're on), you will encounter two trolls. The first is a she-troll being attacked by some mercenaries, so kill them to help her. Follow the path a little further and you will meet her husband, who is looking for her. Obviously, don't attack the husband or select the dialogue that prompts a fight. Agree to help him and go back to the she-troll to tell her to go back to her husband. Convince her to go back to her husband to complete the subplot.
The achievement will unlock after you help the last troll in Chapter II.