As the name implies, it’s a graveyard for beasts. It’s said that the Divine Beasts that fell in that place were the largest out of the Divine Beast Origin, forming into a massive graveyard that is enveloped by a deathly aura all the time over the years. Because it was mixed with the evil aura of the Fiend Clans, it’s extremely dangerous and it’s one of the ominous lands.
There were a few Super Divine Beasts that fell in the Myriad Beast Graveyard. Super Divine Beasts were pinnacles amongst the Divine Beast Clans, comparable to Heavenly Sovereigns.