Like the rest of the dragons, Pyromalfic was spawned by the Dragonfather Lord Toruk when he divided his athanc to create a brood dragons as servants in his image. Unfortunately, Toruk's sons were too similar to him and were unwilling to bow down to anyone, including their father; and they turned on him. Toruk eventually destroyed many lesser dragons, and the rest fled. From that point forward, Toruk sought to hunt the dragons down and gather the pieces of his athanc to undo his mistake.
By 2100 BR, Pyromalfic blighted and enslaved a sect of Iosans, who seized the fortress called the Castle of the Keys, on the mountains of the Bloodstone Marches. He created his lair beneath the fortress complex.
In 1000 BR - by the time Toruk has already consumed three dragons - Pyromalfic participated in an alliance of dragons organised by Blighterghast to drive Toruk from mainland Immoren. The dragons ambushed Toruk, forcing him to retreat to the Scharde Islands southwest of Immoren.
In 230 BR, an Orgoth expedition into the Castle of the Keys decimated the Iosan cult serving Pyromalfic but was defeated by the dragon. A fragment of an Orgoth tome detailing this encounter suggests Pyromalfic was somehow poisoned or cursed.
Several centuries after that, Pyromalfic was reportedly destroyed in a clash with another dragon, Scaefang; though the rumours carrying details of that battle have been questionable. In truth, Pyromalfic retreated deep in the ruins of the Castle of the Keys to recover from his injuries. However, in the centuries following, Pyromalfic's injury healed only bit by bit, and he became convinced something weakened his regenerative ability, perhaps a problem with his athanc, which weighted on his mind for years.
In the spring of 607 AR, the newly-formed Legion of the disembodied dragon Everblight, having been revealed the location of Pyromalfic's lair by Goreshade, march upon the Castle of the Keys intent on defeating Pyromalfic, consuming his athanc and greatly increasing the Legion's power.
Pyromalfic is eventually discovered and roused to battle by a small group of Everblight's minions led by the blighted ogrun Thagrosh, host to the largest portion of Everblight's athanc. He immediately ascends from his lair and quickly gets swarmed by myriad of Everblight's spawn: angelius, seraphim and harriers. Pyromalfic's claws rip through them with ease, but there were too many, and he falls towards the courtyard before his athanc is cut out by the Legion warlock Rhyas. Thagrosh then climbs back to the surface, takes Pyromalfic's athanc and swallows it whole, forcing it down his jaw and throat.
Even after being defeated, Pyromalfic still tries to convince Thagrosh that he isn't an adequate vessel and Everblight will discard him as soon as he can, though his efforts prove futile. Pyromalfic's mind and essence are later fully devoured by Everblight, his athanc and power added to the other dragon's. Pyromalfic only continues to exist as glimmers of a shattered consciousness that once in a while invade Thagrosh's mind.
Pyromalfic's death and consumption alert the threat Everblight proves to the other dragons, and soon after Blighterghast, informed by the blackclad Krueger the Stormlord on the events at the Castle of the Keys, calls the other dragons again, this time not against their father, but against the new threat of their upstart brother.