|This article is about a/an set of items in Doubutsu Sentai Zyuohger.|
The original King's Credential was the Great King's Credential (大王者の資格 Dai Ōja no Shikaku), created by the Earth which resonated with the wish of the whale Zyuman, Cetus, to protect his people and the world from the Ferocious Monster that threatened them. Becoming the Whale Change Gun, the Great King's Credential granted Cetus the power to transform into the first Zyuohger - Zyuoh Whale -, complimented by the first Zyuoh Cube - Cube Whale -, allowing him to defeat the monster. Having saved his people, Cetus was named the Great King of the Zyumans while the embodiment of the Earth's power which he held was named the Great King's Credential. Following this, the Zyumans would create a new world named Zyuland where they could reside in peace, with Cetus using the Whale Change Gun to create a Link Cube to the old world, the Great King's Credential served as the core of the gateway while six additional King's Credentials were created to serve as keys.
The Link Cube allowed the Zyumans to travel to the human world at will until it rendered inactive as one of the King's Credentials had been taken by the eagle Zyuman, Bud, who gave it to a human boy who he saved. The boy, Yamato Kazakiri, kept the cube as a good luck charm and, having grown up to become a zoologist, was eventually drawn by it to the Link Cube. Finding the vacant slot in which the cube fitted, Yamato entered Zyuland and met the Zyuman guardians, who believed him to be the thief. Pursued back to his world, Yamato found it under attack by an alien force known as the Deathgalien. While the Link Cube was damaged by Deathgalien Team Leader Jagged, the four Zyuman guardians each recovered a King's Credential they were entrusted with. Meanwhile, amidst the chaos, Bud's clawed hand took the remaining King's Credential, disabling the Link Cube and leaving the Zyumans stranded. Discovering the King's Credential's power to protect the Zyumans as the cubes became the Zyuoh Changers, allowing them to transform into the Zyuohgers and summon the Zyuoh Cubes, the Zyumans were shocked to see Yamato be able to use their power. A result of the Zyuman Power which Bud granted to him as a child, Yamato's wish to defend his world and all that lived on it granted his King's Credential the form of the Zyuoh Changer as well, allowing him to become Zyuoh Eagle. Following their first battle, the King's Credentials granted the four stranded Zyumans human forms for their protection.
Bud carried the sixth King's Credential with him in his travels until he found Yamato on the verge of defeat by Saguil Brother A, and stepped in to defend him. When he too was overpowered, Bud pleaded with his King's Credential for the strength he needed to protect Yamato, and the King's Credential responded by becoming the Zyuoh Changer Final, granting Bud the ability to transform into Zyuoh Bird.
Ultimately, when Ginis threatened to use the Sagittari Ark to destroy Earth, Bud and Larry proposed returning the King's Credentials to the Link Cube so it could be used to preserve the world in an isolated pocket space. However, the Zyuohgers decided to face Ginis to save the Earth and keep the Earth connected. After prevailing against him, defeating the Deathgalien once and for all, the Zyuohgers returned the King's Credentials to the Link Cube as the Zyuman prepared to return home to Zyuland only to meet the unexpected effect of the Link Cube merging the two worlds into one, restoring the world to the union of humans and Zyumans prior to the Link Cube. Having been approved by the Earth itself, the King's Credentials were returned to the Zyuohgers.
- The Zyuoh Changer's original form's name has a pun, as "Credentials" (資格 Shikaku) is a homophone with "Square" (四角 Shikaku).