Ian's required Demonic Beast materials needed to have "Earth Attribute" and "digestive system" as keywords.
This was actually a very common pairing.
For instance, Elder Prude's Bloodline Inheritance, the "Felsic Bear Lizard," was an Earth Attribute Magical Beast, and its characteristic was its extremely powerful digestive capability, to the extent that it could reinforce its armored shell by swallowing metal veins, and even transform its entire body into a steel rock material that made it resemble a large steel rock when it crawled on the ground.
Other Earth Series Magical Beasts, such as the "Reef-eater Otter" would gnaw on Fortifying Coral, and the "Ironclad Shark," though it lived in the water and could manipulate water currents, when it came to self-strengthening, it was indeed the Earth Attribute Origin Quality at work.
They all possessed a powerful digestive system to ensure the robustness of their bodies.
