Eldigan is the older half-brother of Lachesis, and a close friend to Sigurd and Quan, both of whom he first met at Belhalla's military academy. He is also the husband of Grahnye and the father of Ares, both of whom move to Leonster to stay with her parents before Agustria enters a war against Grannvale. Eldigan is extremely loyal to the Agustrian royal family, as his ancestors inadvertently inherited Hezul's Holy Blood through Hezul's daughter, who was married off to Nordion. They thus swore to utilize the powers of the Mystletainn to protect the royal family. King Imuka was a mentor and close friend of Eldigan, particularly in the latter's youth. While Sigurd is residing in Evans Castle during his invasion of Verdane, Eldigan pays a visit to him in which he promises to watch over Evans while Sigurd marches deeper into Verdane. Shortly thereafter, Prince Elliot of Heirhein moves out to capture Evans, but he is stopped in his tracks by Eldigan and the Cross Knights. Sometime later, Eldigan decides to travel to Agusty in order to convince Chagall to end his military buildup, despite Lachesis's warnings. This results in him being arrested by Chagall, but he is later released when Sigurd conquers Agusty. When meeting with Sigurd, Eldigan tells him that he has one year to restore the peace and leave Agustria. During the next six months, Eldigan resides in Madino Castle with Chagall, while he leaves the Cross Knights at Silvail, prepared to take out Sigurd if he breaks their agreement.