Dr. Serna Nichol is an overconfident young linguist who researches the Nobility and deciphers their ancient documents.
At the beginning of Legend of the War Fiends, Dr. Serna is a part of a survey team investigating an ancient castle that had been abandoned by the Nobility. For two thousand years a massive nuclear generator had been left running nonstop inside this mountain stonghold, but the information as to what that generator was powering had been lost; it is speculated that that had been intentional. It takes the team two days to find an answer as to why the castle had been abandoned and what its purpose had been. It’s from this castle that the giant warrior Dynus tunnels out of, causing a section of the castle’s massive rock walls to collapse and crush ten scientists; escaping unseen though his booming laugh could be heard.
Three years later, Dr. Serna meets D in the town of Schlad when the Hunter requests data from the library in the Capital regarding any situations that resemble the one involving Raya, the young farm girl who embodies Raya the Warrior Woman of Sinestro. When the book D ordered arrives, Dr. Serna arrives with it as he is its author. Serna greets D with a smile and a volume of his latest research in one hand.
Serna follows D back to Raya’s farm. When they arrive, she and Dynus are nowhere to be seen. The Hunter has an idea as to where they might be. Serna tries to follow D, even though he tells Serna to stay; the linguist claiming he can handle a steed. Despite his boast, Serna gives up trying to pursue D as the Hunter is too fast, even though the horse D rides is no different than his own. Dejected, he returns to the farm. While there, he investigates Raya’s house and bedroom. There is no evidence to prove that Raya is who they think but when D explains how she goes under a transfiguration, Serna concludes then that there is no doubt to what or whom she really is. Serna then also deduces that Dynus may have been the one that dug the massive tunnel, as the giant would fit perfectly. D then tells the linguist how they have been looking for a way to keep Raya from changing. From several ancient manuscripts that had been discovered six months prior, Serna believes there is a way to do just that. If the technology remained, they could use it to help Raya.
As Serna, D, and Dynus are about to take Raya to Castle Sinestro, she comes out of her room in her transfigured state. While Dynus and Raya fight, D takes to his horse and gallops toward the forest near Raya’s farm. Serna later catches up to D after saving Brewer, the hunter tells him to get word to the village about the incident then regroup at the castle.
Once there, Dynus creates an entry way into the sanctum below the castle ruins. Once the unconscious Raya is set upon an operation table attached to the machinery that programmed the superwarrior, Serna inspects the equipment. Just as he’s about to start the process, Serna has second thoughts. For him, Raya was a miraculous specimen- being a warrior created by the Nobility. Should she be changed back to a normal girl, he’d lose the chance to study her. Instead of pushing the button to erase the warrior programming, Serna instead throws the switch to the machine allowing Raya to awaken as the warrior. It is because of this that D then slices Serna’s arm off. When Dynus and Raya leave the ruins for what would be their final battle, Serna is then left in the care of Brewer as D goes after them.