The Archmage was a powerful but arrogant sorcerer who was once a courtier at Castle Wyvern. He taught both Demona and the Magus how to use magic, and was the first person known to possess the Grimorum Arcanorum.
In 975, the Archmage sent Demona to steal the Phoenix Gate from Princess Elena, while he was still the premier spellcaster in service to Prince Malcolm. Though he did not act openly, he desired the Phoenix Gate to combine with his Grimorum and the Eye of Odin, which would give him ultimate power. In this instance, he failed to retrieve the Phoenix Gate.
In 984, the Archmage poisoned Prince Malcolm, who had become lord of Castle Wyvern, in retaliation for his banishment. In order to save the Prince, three gargoyles - who would later be named Hudson, Goliath, and Demona - tracked the Archmage to a cave in order to retrieve the Grimorum, which contained instructions for formulating an antidote. During this encounter, he blinded the future Hudson in one eye, then seemingly fell to his death when attempting to retrieve the Grimorum.
The Archmage became a far greater threat when he attacked Avalon. Apparently, he had survived his fall into the chasm by traveling back in time and saving himself. By manipulating events, and coercing the Weird Sisters to do his bidding, he managed to obtain the Grimorum, the Phoenix Gate and the Eye of Odin, granting him the ultimate power he had previously sought. Using his powers, he rescued himself in the past and then arranged for himself to gain the three items, before his younger self set out to do the same in a predestination paradox.
Having gained his new powers, he aimed to conquer the world, but was informed by his future self the technological advances in the modern world would require him to have base of operations where his enemies could never touch him, Avalon, and thus he laid siege to it and attacked the Avalon Clan that lived there. However, he refused to destroy them immediately because he wanted revenge on Goliath and believed that he was invincible. His hubris allowed the Avalon Clan, with Goliath's help, to mount a counter-attack. Goliath managed to steal the Eye of Odin away from him, and without the Eye, he was unable to control the power of the Grimorum, having previously swallowed it in order to circumvent the law that the book could never enter Avalon, and it destroyed him, turning him to a pile of dust.
And he will be voiced by John Noble in the English dub as a tribute for David Warner and his Japanese voice is unknown.