- Order: Leviathan
- Suborder: Leviathan
- Infraorder: Flame Wyvern
- Family: Agnaktor
Agnaktor is at the top of the food chain in the Volcano. Common prey for the Leviathans are Rhenoplos, Slagtoth, and Apceros. Despite its role in the food chain, Agnaktor compete with other large predators. These predators include Rathalos, Brute Tigrex, Stygian Zinogre, Lavasioth, Glavenus, and Brachydios. Brachydios are one of the few monsters actually seen killing an adult Agnaktor.
Agnaktor has developed the remarkable ability to swim through lava, meaning it can both sneak up on prey and escape from a more powerful enemy. It has a very strong beak, which it uses to burrow straight through hard volcanic rock at incredible speeds, and even launch itself into the 'ceiling' of an area and to crack open the sturdy shells of the Rhenoplos. It is also capable of producing a very powerful fire beam, which it can maneuver a full 360 degrees with its long neck. How it produces said beam is uncertain. Produced between Agnaktor's scales is a nonflammable substance that never burns. This substance allows Aganktor to coat its hide with lava and swim in lava. This coats it in lava, which hardens into a thick armor of rock. However, when the Agnaktor touches the lava, its lava coating becomes soft again. Its chest and beak armor will also soften if it fires its beam, which seemingly implies that the mechanism behind its beam attack is related to its chest somehow. Furthermore, its beak armor alone softens whenever it attacks by jabbing its beak through the ground, exposing it to the lava underneath. This harder coat of black rock as it cools down, as well as the softer skin armor when it heats up, may represent a tactical adaptation, trading defense for a fire element or vice-versa.
Agnaktor are reasonably aggressive, challenging all others that encroach on its habitat, due to the fact that it has no natural predators at a adult age. The only threat that it encounters is if a monster challenges it for territory or food. During the Breeding Season, both males and females will swim to the summit of a active volcano to mate, this is also where most Agnaktor learn the dig through the ceiling technique. The female will then make a nest somewhere near the top and then give live birth to 2-30 individuals at a time. Agnaktor who use the ceiling digging attack have mated at least once in their life.