Edmun Dragonsbane is a villain from Dragon's Dogma.
History
Originally just another soldier, one day Edmun awoke as an Arisen. Perhaps it was coincidence, perhaps fate, but just days later, a dragon attacked Gransys. Fulfilling his role as an Arisen, Edmun enlisted a number of pawns and set out to face the dragon. The epic battle that followed would be celebrated in song for generations to come, for unlike so many before him, Edmun triumphed over the wyrm. Slaying an evil dragon—in all of recorded history, there was only one other who had achieved this miraculous feat: the great unifier, Godking Leonart. Yet now, Edmun too had defeated a dragon. With everyone singing his praises, plus the support of the noble Gildas who had long been his ally, Edmun was propelled into the heart of government on an overwhelming wave of support.
A number of years passed. When the former duke fell ill and passed away childless, Edmun was selected as his successor. None contested his appointment to the position of duke for he was one of only two men to ever successfully complete a Wyrm Hunt. To refute him was to refute Leonart, the very father of their nation.
Having been appointed duke, Edmun took the name “Wyrmking” for himself. This title, a reminder of his victory over the dragon, was happily accepted by the people. Under the rule of Wyrmking Edmun, Gransys has seen a long period of peace and Edmun, with seemingly inexhaustible youth, remains hale and healthy to this day.
It is later discovered that Duke Edmun did not in fact slay the Dragon all those years ago. But made a deal with it to make it seem like he did by sacrificing the woman he loved, Lenore. This is also why the Duke has not aged in over fifty years: his heart still belongs to the Dragon, thus, making him immortal. Once you defeat the Dragon, Edmun's heart will return to his body, causing his immortality to disappear. This causes him to turn old as the years catch up to him. When you meet him again after defeating the Dragon, he will believe you have sacrifice your beloved in order to take his throne and proceed to attack you. Upon beating him, he'll call on his guards and brand you a traitor, calling you the Dragon's minion. As to why the Duke's pawns are never found, it is speculated that the woman Lenore, whom he sacrificed was his main pawn, and by sacrificing her he lost the remainder of his soul..this could also explain why the duke has forbidden pawns from entering the castle...for that he will be reminded of the sacrifice he did so long ago against a wyrm that he thought could not best.