Their domain spreads from rocky hills and savannas to mountainous or volcanic areas. They prefer warm environments - colder temperatures force them to feed more often to maintain their body temperature - but can still survive in a colder climate. They are omnivorous, but are primarily carnivores and eat plant material to help fuel their powerful ignition systems. The Crowned subspecies is generally larger and has many scale vents near its head - when it ignites, it crowns itself in flames for a terrifying display of power. The Whiplash, on the other hand, has an enlarged tail and many scale vents near the back of its body. Despite the name, its tail is used less like a whip and more like a burning hammer, scorching its challengers with a hot, crushing blow. The Crowned Fire-Mark has a length of around 9.5 metres (31.2 ft) from head to tail, and a height at eye level of 4.1 m (13.5 ft). With its wings fully unfolded upwards, its height increases to 10.8 metres (35.4 ft). The wingspan is around 14.7 m (48.2 ft) from tip to tip. Mass varies from 4900 to 5800 kg depending on the availability of food and the size of its heavy tail. The Whiplash is slightly shorter and has a smaller wingspan, but has a larger head to tail length of 9.7 metres (31.8 ft). The dense, thick plated tail contributes substantially to its total mass and as such, the largest and heaviest Whiplashes can reach a colossal 6 metric tons.

The key feature of Fire-Marks is their ignition systems, which are unique to their species. Fuel can be released through the vent scales, horns and tail. When ignited, the horns expand by half their size as the interlocked sections slide upwards. The exterior of their bodies is completely fireproof and protects their insides from heating up too much. The main fuel is methane which is produced during digestion and then stored in several containment organs throughout its body. The angled front claws and lower jaw spikes are used to cut swathes of grass to eat or scrape bark off trees. This plant material is better for producing fuel when digested. Its tail has an independent fuel supply. Although it can still supply the tail vents with methane to burn, it can alternatively use ammonia as fuel here, which is produced in its tail from urea. However, this is not as effective a fuel as methane and is usually only used when it needs to conserve methane.