The fleshly body ultimately has a limit to its enhancement.
Even for the Innate Divine Beasts, favored by heaven and earth, their final evolutionary direction is to enhance the fit between themselves and the universe, thus turning themselves into a transmission device between heaven and earth.
As an alien species, Demon Spirits evidently find it difficult to win the favor of heaven and earth; under such circumstances, their evolutionary direction invariably involves self-modification.
Each Demon Emperor is almost akin to a hybrid of biological and mechanical features, forming a powerful weapon.
Moreover, as the materials they use for their transformations are top-notch and their inherent traits as Demon Bodies endow these materials and equipment with strong regenerative properties of living beings, the combination produces an effect greater than the sum of its parts.
Even when struck by Divine Skills, they recover quickly.
