Sezorox

In the vast world of Isteria, every rise of darkness pulls ancient legends back into the light.
Every time a shadow stirs, long-buried legends awaken, and hidden powers return to the surface. The people believe that the gods who once protected the land sent their own children down to earth, reborn as Dragon Knights, guardians chosen to defend Isteria when its fate trembles.
Long ago, the world fractured into drifting realms after the banishment of Vyralith, the Fallen Dragon Sovereign. In a desperate act, the sage Minsu shattered the World-Crystal and embedded each shard into the hearts of chosen dragons descendants born to carry fragments of destiny.

These shards protected Isteria from a power older than the gods themselves:

Sezorox The Primordial Pulse,

the first rhythm of existence, the spark that shaped creation. Too vast to be contained in any single vessel, it was scattered across dragonkind.

Yet the darkest part of the legend is the one told only in whispers:

Before his banishment, Vyralith descended to the mortal world in human form walking among kingdoms, unseen and unrecognized, never revealing his true form to anyone.
None knew the sovereign of dragons lived among them, studying their weaknesses, their fears… and their hopes.

Prophecy warns:

If Vyralith ever recovers his true form and gathers the shards of Sezorox, Isteria will collapse into the Unending Dark an eternal curse no guardian can halt.

And so the dragons became living vaults for Sezorox fragments.