Prism Beast (
In Arc-7, only the seven rainbow-color Prism Beasts exist at first, but Chiharu Nanairo's father expands the Archetype later in order to help them Toolbox more Summons. However, not all of the new Prism Beasts were created, so Chiharu, using a special power she possesses, creates the missing Prism Beasts out of blank cards alongside the rest of the Iridesks, allowing Yushi to pursue his goal of mastering all forms of Summoning.
All Prism Beasts have an effect that adds a Spectrum Piece to the Spectrum Wheel, almost all of them doing so upon being Summoned or being flipped face-up ("Prism Beast - Amber Robo" is the only exception, adding a Spectrum Piece upon being placed in the Pendulum Zone). However, most of them can only add a certain color of Spectrum Piece that matches or relates to their own color. In addition to these effects, their effects usually act as generic LIGHT support.
There are two groups of Prism Beasts: The original 7, and the alternate hues. The original 7 Prism Beasts, which represent the seven colors of the rainbow, focus on manipulating battle positions alongside preparing for Spectrum Summons, mainly to aid in using "Iridesk Hero Nijiyama"'s effect. The alternate-hued Prism Beasts, however, are designed to support all other forms of Summoning alongside Spectrum Summoning, being capable of searching out "Fusion" cards, Ritual Cards, and Splice Spell Cards, as well as having a Tuner Monster, a Dark Tuner Monster, two Pendulum Monsters, and a Base Monster in their ranks.
Because of the Prism Beasts and Iridesks being designed to be used alongside each other in Arc-7, several of their effects have limitations that the Iridesk monsters easily fit within, including searching for Level 7 or lower LIGHT monsters (no Main Deck Prism Beast or Iridesk is above Level 7) or having Level restrictions on what monsters that they can be used to Summon (Level 8 Synchro, Level -6 Dark Synchro, or negative-Level Timewarp, all of which the Iridesks fit).