It was the core area of the Myriad Beast Graveyard, located in the depths of the Graveyard.
In ancient times when the Divine Beast Origin shattered, the powerhouses on this continent had fought against the Fiend Clans and most of them had fallen in the depths of the Myriad Beast Graveyard. When the powerhouses of the Fiend Clans fell, the evil aura from them had attempted to taint the remains of the powerful Divine Beasts. Fortunately, the remnant Wills of those Super Divine Beasts combined together and resided in the depths of the Myriad Beast Graveyard, protecting their remains and suppressing the Monarchs of the Fiend Clans at the same time.