A Demon Seed is a Psycho-physical manifestation of all of a persons so-called 'Dark energies'. The seed is Dehama deposit in the sternum, which turns the bone black. The location of the Demon Seed is marked by the Demon Seal on the skin above the seed. Although physically harmless, the seed can have a major traumatic effect on the mind, causing hallucinations, paranoia, schizophrenia and, though quite rarely, suicidal tendencies. The seed's physical effect manifests in a complete tranformation of the host into a Shargaromalum, or Demon.
Unlike other Psycho-physical ailments, a Demon Seed can only be gained voluntarily as the only way to gain one is to use the Higher Element of Titan. When a mage uses Titan for the first time the are fully aware of the repercussions and therefore know that what they are doing will result in them forming a Demon Seed. The only person ever to have contracted a Demon Seed without the use of Titan is Gallon as he was unknowingly infected by Godslayer through Shan-Dor.
One side-effect of the Demon Seed is that the afflicted will periodically change into a Shargaromalum, or Demon, usualy in moments of emotional stress or after exposure to high amounts of Shargaromalic energy. Fortunately the change is purely physical and has no affect on the afflicted's personality apart from when the afflicted experiences extreme rage when the afflicted's Demon form will devolve into a feral Thnarek. The tranformation itself is painless, although the reason for this is unknown, and is heralded by the afflicted being covered in black smoke. The afflicted gains total control of their transformations after a few months of having the Seed and achieves total spiritual harmony at this point.