Another stab at flavor text, this time being more original.
The draknor is the larval form of a massive extraplanar monstrosity. Although it is still in the larval phase, the draknor is a behemoth on the Material Plane.
Although the reason and method that draknor eggs arrive on the Material Plane is an enigma, they are always found underground, in secluded areas near sources of great heat. A draknor egg is 2 feet long, weighs 8 pounds, has hardness 10, 15 hit points, and a break DC of 13. Within a year, the egg grows to a size of 20 feet and hatches, releasing the draknor.
Once hatched, the draknor immediately sends its tendrils through the earth, looking for a source of heat. As long as it continually feeds on this heat, it gains 1 HD per week. Upon reaching 33 HD, it immediately transports itself (through a one-time
plane shift effect) to the border region of the Elemental Planes of Earth and Fire, where it reaches maturity. (The mature draknor is an epic-level creature and is not detailed in this article).
Although it subsists solely on heat, a draknor is able to consume and digest nearly any substance. This fact, and its preferred habitat, make it a particular threat to illithids and other Underdark races. The draknor's immunity to mind-affecting abilities and
mind blast attacks renders illithids nearly powerless against them.
Although draknor are highly intelligent, their thought processes are totally alien. They cannot (or choose not to) communicate with other creatures.