They can't be destroyed, but you'll be able to pass through them much later in the game. If you want more details/direction let me know. It won't get you through the black barrier but it opens another very roundabout way to get behind the barrier.

That item allows you to access Fog Canyon. Defeating the Dung Defender allows you to obtain a different item from a grove near his arena.

Enter the tower and ride up the elevator. Grab the three Green Blossoms while you're here. Go the lone Hollow Soldier to bring the other Hollows out of hiding. Some bosses are capable of entering into a state of stagger after landing a number of. You will need to perform multiple attacks such as using The Nail and Nail Arts along with the Spells and Abilities in order to defeat them. 1 near the Whispering Root north of the Mantis Village.Watcher Knight is a Boss in Hollow Knight.Bosses are special Enemies that feature their own arena, a large amount of health, and a variety of unique moves and abilities. 1 in the room southwest of where two Shrumal Ogres are encountered. 1 outside of the Stag Station behind a breakable wall. There are a total of 14 Wanderer's Journals that can be obtained: 2 found in Greenpath.