Gogen is an ancient wizard who originates from the kingdom of Orthus and has lived for over three thousand years. He was chosen by the Five Great Spirits to be one of the legendary Seven Braves of Old, a group of warriors who fought to prevent the entity known as the Dark One or the Lord of the Black Abyss from causing chaos in the world. While his fellow Braves ultimately lost their lives sealing this great evil within a sacred relic known as the Ark, Gogen devised a different method to survive. He transferred his own soul into an ancient monolith, effectively sealing himself away until such time as he would be needed again. He waited in this state for millennia near the town of Seirya. It is this ancient monolith that serves as the so-called ancient book which Arc is sent to find, and Gogen is eventually unsealed by the remaining darkness emanating from the Ark, revealing his true nature to Arc and his companions.

In terms of personality, Gogen is a figure of clear contradictions, embodying the archetype of the venerable ancient wizard while simultaneously serving as a source of lightheartedness. He possesses the vast wisdom and knowledge of the world that one would expect from a magician who has existed for thirty centuries. However, this is contrasted by a generally silly and absentminded demeanor, often acting as the witty comic relief within the group alongside characters like Poco. He can be prone to boasting, referring to himself with grandiose titles, yet this is undercut by his tendency to be scatterbrained, likely a result of his extreme age.

Gogen's primary motivation is his duty as one of the Seven Braves of Old. He is committed to preventing the Dark One from plunging the world into chaos once more. This ancient oath drives him to ally with Arc, the new generation's chosen hero, to ensure the Ark's safety and lend his immense power to the fight against the forces of darkness, such as the Romalian army. His role in the story is that of a crucial advisor and a powerful magical ally. He provides critical exposition about the history of the world and the true nature of the conflict, while his combat abilities make him an invaluable asset on the battlefield.

Key relationships include his bond with Arc, whom he serves as a mentor and guide, having been awakened specifically to assist him. He also forms a significant partnership with Lieza; in their shared quest to uncover the fate of her village, Holn, after she is captured, it is Gogen who uses his magic to remove a boulder blocking the village's entrance, allowing them to discover that the Chimera Labs had abducted the citizens.

Throughout the series, Gogen demonstrates notable development by consistently reappearing across different eras to lend his aid whenever the world is threatened. Following the destruction of the original Ark, a catastrophic event with dire consequences for the world, Gogen uses his ancient knowledge to assist Alec and his allies in the creation of a brand new Ark to once again seal away the Lord of the Black Abyss. In later years, he retreats to Elbow Cape in Jiharta, where he continues to involve himself in world events, such as playing pranks on treasure hunters by charming treasure chests, and offering his counsel to a new generation of heroes by suggesting they unite the Spirit Shrine Maidens to defeat a new evil known as the Black Knight.

Gogen is a mage of extraordinary power, and his strongest attacks are his diverse magic spells. He possesses a wide arsenal of elemental damage magic, including powerful fire, lightning, and explosive spells capable of devastating large targets. Beyond raw offensive power, his repertoire includes highly versatile utility magic; he is notably one of the few characters who can cast Teleportation magic, allowing him to reach otherwise inaccessible areas. He also has access to spells like Rob Mind, which drains magic points from enemies, and Dream Nok, which can put all enemies within range to sleep without dealing damage, demonstrating a mastery of magic that extends far beyond simple destruction.