The Marshes is an area containing multiple key objectives, most notably the Landkeeper HQ. Hostile Trapwurm hide beneath the ground and engage the player at random.
Since version 1.8, the New Landkeeper Hideout can be accessed from The Marshes after the completion of the main game story. The entrance is located beneath the Landkeeper HQ.
Cave
Straight east from the Marshland Cave entrance is a smaller cave filled with water. Inside is a cache containing a Rogue Fusion.
Campsite
Campsite: Near the center of the Marshes is a campsite where the player can rest at. Straight ahead is a cache which causes Viola to appear.