During the second chapter, you will encounter a fully armored enemy. You can't go around him. You must face this enemy in an open fight. Below you will find a detailed description of how to defeat him.
Dodges play a significant role here. First, you need to knock down his two shoulder pads. They are attached with circles on his back. Running in a circle around the enemy is useless - the enemy will always face your direction. Instead, wait until he gets close and starts attacking. Dodge his attacks. The impact force will make the ax stuck in the ground for a moment. He will need some time to take the weapon out. Approach the enemy from behind and knocking down the circles.
Remove the shoulder pads to expose the neck armor mounts. They are located on the enemy's chest. You can shoot them down when he is walking in your direction. You have to stand at the right distance or dodge immediately after the shot. Otherwise, you will die.
The last thing you have to do is to remove the helmet. Its mount point is in the middle of the knight's back. You need to dodge his attacks again. At this point, you can take advantage of the fact that your opponent starts getting tired. He will stop for a moment to regain stamina. This is the perfect opportunity for you to shoot down his helmet.
Lastly, you have to shoot his exposed head.