Rare Kind
Rare kinds are people with the ability to negate the special powers of others. They are unlike other power users in that their lost form requires an exlir to restore their orginal form. Their blood is also needed to open pandora's box.
Known Rare Kinds
Powers
Ability Nullification: Rare kinds have the ability to negate the special powers of others. It seems that this power is in their blood as shibuya's costume is coated with his blood and special powers cannot affect the costume as well. Another example is that the new school building was built with shibuya's blood mixed in, making it so that special powers couldn't be used in the school.
Shrinking: It seems that when a rare kind over uses their power they shrink to a small doll size. This is unlike other "lost forms" in that after 24 hours they still do not return to normal. A special exlir made with the blood of a rare kind is required for them to return to normal.