Serellion is known to have grown larger than Vhalax, the dragon of Aeganar IV during his reign. His scales are as black as coal, and his eyes are a beaming orange, much like his own rider, as if they were created for each other. His claws are as sharp as scythes, and his teeth are easily the length of longswords. His wingspan could cast a shadow over an entire town, much like Gavarex. According to dragon lore, some puportedly written by Aenarion himself, dragons continue to grow if their health is maintained well -- and Serellion was well taken care of.
Serellion was given to Taeronys during his childhood, as a hatchling. As a hatchling, he was the size of a child, and at first glance, about the same size as Taeronys at the time. Queen Rhaenera, Taeronys's mother, would often worry about him getting hurt by the whelp, and had a nervous demeanor around the hatchling. Serellion had accidentally burned Taeronys's finger once, but that did not halt the development of their bond.
Taeronys and Serellion grew together over the years, and since then, acquired a near-unbreakable bond. Serellion grew abnormally large, even when he was only 10 years of age he was as big as a large wagon and had to be taught more vigorously than before. Serellion was used to sleeping in the bed with Taeronys; now if he did it, he'd crush him. Taeronys wished he could ride his dragon, and made this quite clear to both of his parents, but they had refused. This did not stop him however, as he ended up riding him anyways, flying out from the window of his quarters and soaring above the Dragonspire, making it a habit to mark all landmarks of note that he could see from his aerial perch. Taeronys grew infatuated with the feeling and adrenaline that came with the feeling, and would train himself and Serellion on how to cooperate with each other while in flight.
When Taeronys was given his own land to govern, Serellion had been built his own castle to roost in. During the Siege of Dragonspire , he destroyed siege weaponry like cheaply-built toys and burned thousands of men alive in their armor, set out as if they were roasting. Through the course of the siege, Serellion was seperated from his master, when Taeronys had to escape Dragonspire before being overrun and risk being killed. Only Vhalax's body was recovered after the siege, so the possibility of Serellion's survival is likely. Citizens have reported dragon sightings ever since, on both continents. Roars can also be heard that are much deeper and guttural than other dragons, and several scholars have pointed similarities to roars of grief -- perhaps it is Serellion's own voice, calling out for Taeronys?