Onyx dragons inhabit dismal swamps and dark fens. They are not especially intelligent dragons, but are cunning and stealthy when hunting prey.
At a distance of 120 feet or more, the onyx dragon cannot be distinguished from an obsidian dragon, unless there is bright sunlight (in which case the dragon’s bright scales are conspicuous). At closer range the onyx dragon’s lustrous, jeweled scales shimmer and sparkle in the light, revealing the mighty reptile’s true nature. In sunlight, the onyx dragon’s deep black scales shine as brightly as a thousand mirrors.
Onyx dragons speak their own language and the tongue known by all gem dragons. They also know a smattering of common (or perhaps another humanoid tongue spoken by creatures nearby).
Habitat/Society: Onyx dragons lair in wetlands, ranging from the tropics to the chillier fringes of the temperature zones. As a rule, they prefer dark, well-shaded areas such as tree-filled bogs. In darker areas, their scintillating scales are less likely to give away their location to prey.
Ecology: Onyx dragons hunt the largest animals in their environments: alligators, herons, manatees, moose, and so forth. They do not hesitate to consume humanoid prey, but they do have enough intelligence to realize that adventurers may be more trouble to kill than the meal is worth.
Onyx dragons do value treasure, especially dark and lustrous gems. However, they tend to have less treasure than other dragons.