Mask Maker provides "faces" for the faceless of the Kingdom. They compare a mask to a face and believe that a face is needed to define, to focus, and to exist.
While they say that they will provide masks for the Kingdom, none of the masks which can be seen in their room correspond to the head of any bug found in Hallownest. Mask Maker comments on this, claiming that in Hallownest it is difficult to decipher whether a bug's face is a mask or their actual face.
Mask Maker knows about the Vessel corpses sealed in the Abyss and about the ancient caste's attempts at ruling the entirety of Hallownest. They also have knowledge of the Knight'sVoid nature.
The Mask Maker is found in the northwest corner of Deepnest. They sit behind a desk surrounded by masks of all shapes and sizes, mumbling to themself and frantically working on simultaneously carving and painting more masks.
Performing Desolate Dive or Descending Dark on them reveals a grey face with swirling eyes. However, Mask Maker mentions that this face may simply be "another mask".
Is it mask or face upon the creature? In Hallownest, a difficult thing it can be to decipher.
A wonderful thing to have, a face. Not a thing with which we all are blessed.
For this kingdom's faceless, I shall provide.
A mask! A face! Does it need one? Does it not? To define. To focus. To exist.
...Does it know of the face that hides beneath? Such remarkable contrast the Wyrm conceived....
It sees the face beneath! Or could it be just another mask?
Truth in Hallownest is always buried deep. How many layers will it pry through?
To change a face; to conceal it fully within another... A powerful protection that is, but one with sad consequence.
The original mind is destroyed, though those of striking will may still retain a sliver of that concealed self.
I see another takes mantle of king? Then grim responsibility that shall bestow.
No bug has ever laid claim to this whole. Even the beasts knew their limits and bound their realm at Nest's edge.
It is the ancient caste that made attempt at such vast rule. Hallownest's ruin reflects well those fared attempts.
↑Mask Maker: "For this kingdom's faceless, I shall provide. A mask! A face! Does it need one? Does it not? To define. To focus. To exist."
↑Mask Maker: "Is it mask or face upon the creature? In Hallownest, a difficult thing it can be to decipher."
↑Mask Maker: "Has it witnessed that truth most tragic? The Wyrm's great shame sealed away." "No bug has ever laid claim to this whole. [...] It is the ancient caste that made attempt at such vast rule."
↑Mask Maker Dream Nail dialogue: "...Does it know of the face that hides beneath? Such remarkable contrast the Wyrm conceived...."