The Knight Phantoms reside in a brick-layered room in the Goblin Knight Stronghold. They appear as ghostly pieces of Phantom armor, and appear to have a spooky, ghost-like look when attacking.
These cursed knights retain 2 attacks.
Their first attack is charging, which is the usual ramming into the player. Like their weapon throw attack, the empty space within them is filled with a scary apparition before they charge.
Their second attack is throwing weapons. While the phantoms with swords cannot throw anything, the phantoms with axes and pickaxes could throw them in a certain direction. As well as this the phantoms with pickaxes could throw them all around their radius. Like the charge attack, they will also turn to a scary look before throwing a weapon.
Once you kill all 6 of the Knight Phantoms, a treasure chest will appear in the middle of the battle area. The chest will contain most of the Knight Phantoms' gear, such as Knightly weapons and Phantom armor.
Using the progression system, the area beneath the trees in the Dark Forest will be filled with smoky ribbons of dark magic. You will be affected with blindness if you stay in the area. Defeating the Hydra will allow you to enter unimpeded. You will also need the Hydra Trophy to unlock the lower levels of the Goblin Knight Stronghold.
Defeating the Knight Phantoms will allow you to interact with and enter the Dark Tower at the center of the dark forest.