Enemies from Hollow Knight. Siblings are entirely black except for their large eyes, which are solid white. Their heads are the only part of them with a stable shape, although that shape varies between individuals. The rest of their body is an amorphous mass of black tendrils.
Siblings greatly resemble the Knight (Hollow Knight)'s Shade. They can usually be differentiated based on their Horns. The Knight's Shade will always have the same characteristic horns as the Knight: long, with an inward curve and notches on the end.