Magma Demons are formed from lava and are roughly comparable to a human adult in size and shape. They are about 2.5 meters in height. Their bodies are pure scarlet and they are wrapped by faint wreaths of flame.
Magma Demons are extremely strong and possess great defense. Their power is comparable to that of Barker's when he just reached the Saint level and transforms into his Undying Warrior form, though their defense is not as good. However, they can easily be one-shotted by peak level Saints like Linley in Book 11.
They use heavy weapons such as stone axes and war hammers, but there is nothing remarkable about their weapons.