Lava Armor
Hunters will first find the Agnaktor wandering the western-most portion of the Volcano map for their initial and subsequent encounters against the super-sized Uroktor. Agnaktor will have usually coated itself with fresh lava at this point, allowing hunters to directly damage the monster before its "magma armor" gradually cools and hardens. When the "armor" hardens, the Agnaktor no longer appears bright orange and instead becomes largely dark brown. Even weapons with Blue sharpness will largely bounce off the Agnaktor in this form; one option at this point is to wait for the monster to become covered in molten lava again.
This can happen in several ways. The Agnaktor regains its orange lava glow whenever it renters lava, intentionally or not; for example, the Agnaktor may find itself sitting in lava again after a charge attack. It also becomes covered in lava when it burrows into the ground like a mole beak-first, and re-emerges from underground. Be warned, the Agnaktor never goes underground unless it intends to launch a series of surprise attacks against hunters!
Should the Agnaktor remain in its hardened armor form, hunters still have a chance to inflict damage by waiting for the monster to launch a lava laser beam (seriously) attack. This attack is heavily telegraphed, signalled by the loud clicking of the Agnaktor's beak as it prepares to fire the beam. Its chest and beak glow bright orange with lava during this attack, offering players more weak points to attack; these portions of the Agnaktor remain in lava form even after the laser attack has long finished.
If the hunter is successful in breaking the Agnaktor's beak, chest, or any of its four legs, the monster loses the ability to protect that part with lava armor. Diligent hunters can thus create more and more weak points to attack as the fight progresses, provided they are skilled enough to break enough of the Agnaktor's parts!
The Agnaktor certainly isn't sitting around the whole time. It attacks in patterns similar to the Lagiacrus when on land; the Agnaktor is naturally much faster! In addition to charging directly at the hunters or advancing while hammering its beak on the ground, the Agnaktor will also attempt hip checks from a distance; this attack is signalled by the Agnakor rearing to its side while its head remains locked in the direction it intends to attack toward.
The Agnaktor also "coils" and "unwinds" itself like the Royal Ludroth and Lagiacrus, in an attempt to drag the player into the coil, or simply swat them with a neck or tail sweep. Like the water leviathans, the Agnaktor only ever coils to its left, meaning hunters often have a better chance of reacting if they choose to attack the lava beast from its right. However, the Agnaktor changes its facing everytime it completes its coil attack; if the Agnaktor was facing left before "coiling", it will now face right, for example. The Agnaktor can choose to use its coil attack multiple times in a row.
As mentioned earlier, the Agnaktor can burrow itself into the ground using its beak. Once underground, the monster can burst from it in several ways. One of the most dangerous is through a series of arcing attacks where the Agnaktor suddenly emerges from the ground before burrowing back into it in an "arc" shape, hoping to hit hunters in the process. The Agnaktor will often pull this off several times in a row. The Agnaktor may also burst vertically from the ground to re-enter the ceiling above, then from the ceiling back into the ground at location ideally near the hunter. Be especially wary of its "shark" like attack where the monster charges directly at the hunter from underground with its dorsal fin still above ground.
When the Agnaktor lets out a roar after it re-emerges from the ground, it signals the end of its underground attack patterns; note that it makes the ground tremor when it lands, stunning nearby hunters very briefly. If Agnaktor only emerges halfway (from the chest up), it will begin firing its lava laser in all directions. Hunters can avoid this laser show either by making a mad dash to the Agnaktor (the area directly around it is safe), or running as far away from it as possible! The 360 laser is a nasty surprise, but also leaves the chest and arms vulnerable for retaliation so getting close is a far better option. Additionally, the Agnaktor requires a bit more time to fully pull itself out of the ground after completing its laser attack.
Breakable: Beak (must be broken for a chance to earn as a reward), Chest, Claws x 4 (all arms must be broken for a chance to earn any number of Claws as a breakage reward, though hunters still have a tiny chance of receiving these as a basic quest reward), back armor, tail