Vellumentals

The Vellumentals are a group of elemental, deity-like creatures that reside in their own Vellumental shrines and temples, acting as bosses in Paper Mario: The Origami King. Their shared name is a portmanteau on "elemental", and "vellum", a type of parchment specifically made of calfskin (alluding to the ancient nature of the Vellumentals).

When they are defeated, they unveil a Bibliofold that allow Olivia to transform into one via a corresponding Magic Circle, allowing Mario to access its elemental powers. King Olly also possesses the ability to turn into each of the Vellumentals in the first stage of his boss fight.

The Vellumentals appear to have a connection with the Shangri-Spa, as the Sea Tower, the entrance to the Shangri-Spa, worship their images.

Members
Each of the members represents a different element:

Trivia

 * The Vellumentals are somewhat based on the Four Symbols, elemental deities of Chinese mythology, at least on a visual level. The Earth Vellumental resembles the Black Tortoise, the Water Vellumental resembles the Azure Dragon, the Fire Vellumental resembles the Vermilion Bird, and the Ice Vellumental seemingly resembles the White Tiger.
 * Elemental-wise, however, only the Fire Vellumental's matches the Wuxing of the Symbol it's based on; the Black Tortoise's is Water, the Azure Dragon's is Wood, and the White Tiger's is Metal. There does not exist an Ice Wuxing, and the Earth Wuxing is reserved for the Yellow Dragon.