Legendary Knights Starting with Oz

Eight hundred years ago, the alchemist Kara was ordered by the first King Oz to secretly create the Dinosaur Core Coin, which symbolized nothingness and would allow the king to better control the greedy. To preserve this secret, the first King Oz severely injured and sealed Kara away.
Located beneath the Kara Alchemy Workshop, in a secret chamber unknown to anyone, ten pure white Core Medals, never before seen, came to life the moment Kara was sealed away. The last and most perfect set of Core Medals, created by Kara with all her life's blood, gave birth to a greedy being who should not have existed, a greedy being named "Regedo" by Kara.
Thus, the third being to possess the power of Oz was born in the Heisei era.