Eldora is described as a man with a red demon eye. He has white hair and a third eye on his forehead.
2,000 years ago, Anos created the Seven Demon Elders from his own blood. After Anos's sacrifice, the Seven Demon Elders co-operated with the Hero Kanon to create the fictional Demon King Avos Dilhevia as a scapegoat for the human's revenge in Anos' place. Kanon then fused his sources with 6 out of the 7 Demon Elders, including Eldora. He also erased their memories so that if they ever came in contact with Anos after reincarnating, he will not know of their plan, as the Elders could not lie to Anos.
During the academy exchange with Hero Academy, the remaining Demon Elders disappeared from Dilhade and were sighted entering the human royal capital Gairadite. Though at first, they were hiding, Medoin Garsa, Zorro Angart, and Eldora finally made their move by attacking the temple holding the legendary holy sword of the Hero Kanon. By the time Anos arrived, the trio had already succeeded, as Avos Dilhevia was able to draw out Evansmana. The ensuing confrontation between Anos and Avos doesn't last long, and Avos leaves with the trio to broadcast a declaration of war all over Dilhade against the human capital.
Following the declaration, the demon army settled on the Eiyan Hill from the Dilhade side of the Tora Forest, creating many demon king castles as their headquarters. When Anos attacked the army, Eldora and the other two Demon Elders flew out to intercept him but were stopped by Melheis Boran and the other Demon Elders allied with Anos. Once Anos made it to the main castle, he was informed by Melheis that Eldora and the others were captured, but that the sources from the people who controlled them escaped.