Nightpyres are usually black, dark gray, or rarely dark red. They are quite small for firedrakes, only about the size of an Icewing Firedrake. They have narrow wings and heads, with four short horns that curve up and narrow, piercing red eyes. Wing membranes and the rings on the tail are usually bright crimson or gold. Nightpyres are the only firedrake species that usually stands on its hind legs, though they may be seen on all fours. The points on the arrowhead tail rake sharply forward to make a sort of three-pronged blade on the tailtip. A low row of narrow spikes runs down its back. In addition, the hind legs have short, upward-sweeping blades on the knees.
The Nightpyre Firedrake is actually a sort of subspecies of Darkwing Firedrake, having split off from the breed early in its evolution. They are built for speed and agility rather than the sheer strength of their larger relatives. This could be a result of some environmental factor forcing them to downtrend in size and thus being forced to flee from larger dragons who would hunt them.
Nightpyres live in warm hills and mountains, and have fairly large, expansive territories that may include the territories of other species. The terrain is often rocky or otherwise uneven, as these small dragons enjoy using the uneven shadows and hiding places to their advantage.
These dragons are not as aggressive as Darkwings, but are still dangerous to approach if in the wrong mood. They are extremely intelligent and will attack in groups to bring down a large enemy. These groups are akin to wolf packs in that it often consists of a mated pair as leaders of its offspring and relatives, and the occasional tagalong. Hierarchy can be rather strict but this is rare, and the group tends to take care of all the hatchlings rather than parents only taking care of their own. During the day, these dragons are lethargic and spend their time basking in the sun.
Nightpyres are resistant to heat as all firedrakes are. Like Darkwings, they are known to have abilities relating to the control of dark energy, this however is not inherent in the species and is only common. They also often have fire-related abilities, such as control of it or Spectrum Firebreath.