Pure Demons can't exist on Midgaardia without the support of some major Magic. To bypass this, Demonkind occasionally impregnate human mothers, and the result is a Demonseed. These children stop aging at about 10 years old, and begin to develop a demonic appearance. They are incredibly fast, surprisingly powerful magically and physically, and irredeemably evil.
Demonseeds have RACIAL-EVIL, RACIAL-NOSUN and RACIAL-SNEAK.
There are even rumours of a path of transcendency to become a Demon for Demonseeds, but if this is the case then Midgaardia is surely not the place to contain this power.