Gan Fall is a prominent figure from the Skypiea arc, known as the former and eventual two-time God of Skypiea who, after being overthrown, took on the persona of a mercenary called the Knight of the Sky. An elderly man of average height, he is distinguished by his long white hair, a thick mustache, and a pointed beard. His original knightly persona is reflected in his full suit of medieval-style metal armor, complete with a billowing cloak and a raised visor, an image that later gives way to a more casual look after he reclaims his divine position. Notably, like his usurper Enel, Gan Fall does not possess the feathered wings common to most other Skypieans.

A noble-hearted individual, Gan Fall is defined by his profound compassion and a selfless dedication to the welfare of all people in Skypiea, often risking his own life to help strangers. He is a firm believer in diplomatic solutions over violence and consistently sought reconciliation with the Shandia tribe, opposing the centuries-old war that plagued his land. This pacifist philosophy stems from a deep sense of duty and a governing wisdom that values understanding over aggression.

Before the events of the story, Gan Fall reigned as the God of Skypiea for decades. Roughly twenty-five years prior to the Straw Hat Pirates' arrival, he met and befriended Gol D. Roger, aiding the future Pirate King and his crew during their visit to the sky islands. He attempted to broker a lasting peace between the Skypieans and the Shandia over the sacred land of Upper Yard, but his efforts were complicated by long-standing enmity and the uncompromising demands of the younger Shandia warriors. His rule came to a violent end when Enel and his army invaded, soundly defeating Gan Fall and seizing the title of God. Deemed too old for slave labor, Gan Fall was cast out of the country but survived, retreating to a secluded home where he grew pumpkins.

During the six years of Enel's tyrannical reign, Gan Fall adopted the alias of the Knight of the Sky. In this role, he functioned as a mercenary, patrolling the skies on his trusted partner and using special whistles to rescue those in need. His role in the narrative is that of a wise and powerful ally to the Straw Hat Pirates. He saves the crew upon their arrival in the White Sea and provides them with a whistle to summon his aid. Throughout the Skypiea arc, he serves as a protector and guide, saving Conis from Enel's judgment, rescuing Tony Tony Chopper from the priest Shura, and later aiding Nami in battle. His deep knowledge of Skypiea's history, including the origin of the conflict over Vearth and the legend of the golden bell, provides crucial context for the Straw Hats.

Gan Fall's key relationships are central to his character. He holds a deep, righteous anger toward Enel, viewing his successor as a cruel and inhuman "God of Evil" who enslaved and killed his Divine Squad. His complex relationship with the Shandia, particularly the warrior Wyper, evolves from one of mutual distrust and hostility during his rule to a reluctant alliance against their common enemy, Enel, ultimately leading to a peaceful coexistence after the tyrant's defeat. His bond with the Straw Hats, especially Monkey D. Luffy, is one of mutual respect, and he notes the strange similarities between Luffy and his old friend, Gol D. Roger.

Despite his advanced age and noted decline from his prime, Gan Fall remains a formidable combatant who compensates for any lost physical strength with wisdom and experience. His primary asset is his constant companion, Pierre, a large bird who ate the Uma Uma no Mi, a Devil Fruit that allows him to transform into a horse or a pegasus, granting Gan Fall aerial mobility. In battle, he wields a steel lance with great skill and incorporates dials into his fighting style, most notably an Impact Dial concealed within his left gauntlet, which can absorb and redirect kinetic force. Though he is unable to use Mantra, the Skypiean form of Observation Haki, his combat prowess is such that he could hold his own against the priest Shura, a confirmed user of the ability. Throughout the Skypiea arc, Gan Fall develops from a deposed ruler in hiding to a key figure in Enel's Survival Game, surviving until the final moments and directly challenging the false god before being struck down by a lightning attack. Following Enel's defeat at Luffy's hands, the people of Skypiea and the Shandia alike welcomed him back to reclaim his rightful position as God, finally allowing him to oversee a unified and peaceful Skypiea.

For the specific film adaptation titled One Piece: Episode of Skypiea, no distinct or contradictory character information for Gan Fall is available in the provided search results.