In the "Black Iron World", Demon Divine Beasts are extremely rare, almost countable on one hand. Usually, only the leaders of the Ten Great Giant Cities are granted a Demon God Core by the Upper Realm. As for the Demon Divine Beast owned by Yano of the "Black Dragon Giant City", it was a separate unexpected encounter of his. "Black Dragon Giant City" owning two Demon Divine Beasts is indeed a special case in the entire "Black Iron World".
Not only in the "Black Iron World", but also in the Upper Realm, Demon Divine Beasts are very rare and precious.
