So did anybody else manage this yet?
Not very clear, but yeah I got every single one
Xaxis - fathom crypt - mega maze mash up - dark forest achievement
Zyla doom - balefort castle - hidden passage 4
Vyxnaar - fathom crypt - the forbidden crypt
Skeller krunch - fathom crypt - a secret passage
Fridge - lost expedition - a hidden ice cave
Shadow demon - shadow caves - cave of shadows - ao1 achievement
How to find them:
Mega maze mash up - you can enter this area from the join game screen or host a game in this area
Hidden passage 4 - as you enter balefort town, turn a full 180° and walk until you can turn right. Make the right turn and there should be a grid right in front of you, enter it.
Forbidden crypt - do the same as you would for hidden passage, but run straight past the grid and go through the portal. After entering the portal, run straight ahead until you are forced to make a turn, turn right.
A secret passage - Enter Fathom Crypt town and go into the sarcophgus
A hidden ice cave - in the lost expedition town there is a guy called Ryom. Behind his shop is the grid that you need to enter to reach the area.
Cave of shadows - in alien oasis town, go to the museum and turn right into the place where you craft the mystery weapons. Enter the grid in the corner.