Arcanicus gland

A red dragon emits magically flaming breath, an effect supported by a dragon's drathyrum-producing superior arcanicus gland.

Arcanicus glands are features of draconic anatomy that generate and regulate magical energies. They are present only in true dragons. Many of these glands produce, use, or regulate the magical ichor drathyrum, which varies in composition by draconic species and is a vital component of several uniquely draconic functions, including dragons' powerful magical breath.

Dragons typically have three or four arcanicus glands:

• The superior arcanicus gland, which is about the size of a dragon's eye and composed of porous flesh protected by the arcanic process bone spur at the third vertebra. It constantly secretes drathyrum into the dragon's throat, which is consumed when the dragon emits its powerful breath or drains into the dragon's stomach.
• In dragons with a second type of breath, the inferior arcanicus gland opposite the superior arcanicus serves the same function but is smaller.
• The aortic arcanicus gland at the base of the dragon's aorta reabsorbs drathyrum into the dragon's blood to reinforce its muscles and bones. The pericardial arcaduct runs from the dragon's small intestine to the aortic arcanicus gland.
• The gastroarcanicus gland in a dragon's stomach secretes a magical slurry that allows a dragon to digest otherwise indigestible matter, minimizing its waste and optimizing its nutritional absorption.

In academia

Debates amongst sages question how the superior arcanicus gland produces drathyrum. One theory holds that the gland absorbs nearby magical energy that the gland infuses into the secreted ichor, while another suggests the gland itself produces sparks of arcane energy.