Obsidian Dragon

Obsidian dragons were the most intelligent of the gem dragons, but also the most dangerous.
Obsidian dragons ranged in size from small wyrmlings to gargantuan great wyrms. As hatchlings, their scales were rough, dark grey, and distinct from each other, but as they grew, their scales changed to solid black and smooth to point that individuals scales were difficult to distinguish.
Personality Obsidian dragons, though extremely intelligent, were also arrogant, quick to anger, and cruel, being known to toy with their prey before finishing it.
Abilities Like other true dragons, obsidian dragons radiated a fear-inducing aura. They were creatures of fire, immune to its effects but vulnerable to those of ice and cold. They also possessed the ability to innately shift themselves from the Material Plane to the Inner Planes at will. The breath weapon of obsidian dragons was a cone of fire.
By the time they were young, obsidian dragons would begin to develop natural psionic powers, at first being able to use firefall, and then biofeedback as juveniles, burning ray as young adults, whitefire as adults, wall of ectoplasm as mature adults, ectoplasmic armor as old dragons, flaming shroud as very old dragons, and plane shift as ancients, of of which they could use thrice each day. They gained the use of mind store as wyrms and genesis as great wyrms, both of which they could only use once each day.
Additionally, obsidian dragons manifested mind thrust/thought shield as their attack/defense modes, and gained powers similarly to a psion of the Metacreativity discipline.
Combat Obsidian dragons were unafraid of combat, making rapid analyses of their opponents in seconds and attacking accordingly; or, more rarely, retreating to avoid or ambush foes too powerful for them to quickly overpower. They preferred to start combat using their breath weapon and ranged attacks, before closing to use physical attacks to finish enemies off. A tactic they particularly favored was snatching and enemy and plane shifting to the Plane of Fire or their demiplane (if the latter's environment was hostile enough).
Ecology Obsidian dragons preferred warm mountainous or underground environments (such as by volcanoes many were known to make their lairs in coal mountains found in the Elemental Plane of Fire. The exception were the great wyrms, who used their genesis power to make their own demiplanes.