Sable

This achievement is available to unlock as soon as you leave Ewer and reach the second area of the game. I would however recommend that you make your way to Burnt Oak Station camp first. If you go there you can pick up a quest from the innkeeper Ifaa that will put the area on the map where we want to go. The so called Hercules Beetle Nest located in the deep south part of the map.

• When you arrive at the main entrance of the Hercules Beetle Nest follow the main road up until you reach a courtyard area. Here you should see a giant Hercule Beetle inside of a tunnel. This is not the one we want.

• Continue past the beetle on its left and you should run across another tunnel this one empty. Enter this tunnel and the achievement should unlock!

Video for those that like those better.