Dark Messiah of Might and Magic Elements

To kill the Pao Kai, as soon as it appears, pull out your bow. Shoot it once, and as soon as you shoot it, turn around and walk through the door you came through to fight it.

On the wall to your left will be a lever. As soon as the Pao Kai dives into the door, shut the gate on his head by pressing the lever.

Achievement unlocked.

As it says on the Achievment descpriction, you will bump into the PaoKaï on
Chapter 5: Temple of the Spider.

In case you aren't familiar what a PaoKaï looks like, it is basically a dragon.

Below I will show a video of someone showing you how to kill the PaoKaï.

As soon as you kill the PaoKaï, the Achevement is yours.

This Achievement says it's missable. I can ensure it is not.

UPDATE #1 My theory was right, this Achievement is Story related.

NOTE #1 The game in the video will look different because it is played on
the PC.

I also like to thank the YouTube user for uploading their video.

Before you give me a negative vote, please explain yourself why you did it and I will be more than happy to improve my solution. Thank You.