The Witcher 2: Assassins of Kings

You can complete this at any point in the story as long as you have upgraded the Deflect Arrows ability to level 2 under the training skill tree.

Once you have this ability unlocked and upgraded, you then need to locate an enemy with a bow or crossbow. This shouldn't be too difficult as there are plenty of enemies in the game with them. But bandits usually carry them. If you have passed chapter 2 like I did, then you can find several bandits in the forest north of Vergan.

When you locate your enemies, make a save and then use your sword to block. Blocking will deflect any arrows back towards the enemies that fired that at you with the upgraded ability. If you manage to kill an enemy with the deflection and this doesn't unlock, reload your save and use your silver sword. As you can see in the video below that my the main sword doesn't always unlock this achievement. So, you may want to use your silver sword the first time.

If you manage to pull this off with either sword, but still don't unlock this, it's possible that the enemy threw a knife at you instead.

First you must purchase both Deflect Arrow skills under the training skill tree. This gives you the ability to deflect arrows back at the shooter by holding Right Trigger.

The earliest archer I have found are towards the end of Chapter 1, after siding with Roche in the At a Crossroads quest, you will have to infiltrate Loredo's mansion. After jumping down there will be a merchant you have to take out, then in the main courtyard there should be ~5 archers. Simply alert them and stand still holding the Right Trigger. Note that you must KILL the archer with the arrow, so it you will most likely have to deflect a few arrows until he dies.

Make sure you have the Deflect Arrow skills from the training skill tree. For those who choose Iorveth's path at the end of chapter 1, you will have a great spot to get this. After you talk with Iorveth and head out to attack the prison barge you will lead them all around the outskirts of Flotsam. After you attack a couple set of guards you can seperate by jumping down to the beach where you first traveled at the beginning of Act 1. The first group I encountered had 2 guards with swords and one archer. I killed the guards and let the archer keep shooting me while I held RT down. This deflected the arrows and killed the archer. I didn't get the achievement until he died.

Just wanted to add this for those who choose Iorveth's path as this was the earliest spot I saw for me.