Demi-human is the name given to several species of intelligent, sentient creatures that inhabit El Nido. Their true ancestry unknown, they are probably descended from Human matings with Dragonians or Mystics who originated from Chronopolis. They may also have been purposely created by FATE as part of its paradise of El Nido, as FATE could transform humans into similar creatures (as it did with Wazuki, who became Lynx). They include an insect-like green species, a robust, furry variety, a mermaid collection, a fat, birdlike species, and other variations of an amphibian nature. When El Nido was first settled, the Demi-humans created their central town in Marbule, researching medicine and safeguarding lore concerning the Dragon God (as the Black Dragon was installed in Marbule by FATE). Many Demi-humans lived abroad, working in Guldove or settlements on the main island. They blended harmoniously with nature and humans, enjoying a paradisical life as FATE intended El Nido to impart.
However, the introduction of humans from mainland Zenan seriously disrupted their way of life. Demi-humans were almost unanimously discriminated against by the new humans, who pushed them out of their settlements and exploited them for cheap labor. Most of the demi-humans retreated to Marbule, where a progressively anti-human ideology emerged; the unfortunate ones served in backbreaking labor primarily as dockworkers in Termina. The Dragonians became completely extinct, putting an end to the festivals once attended by the Demi-humans. The new Marbule desired to shut itself off from the rest of El Nido. This was achieved until after 1000 A.D., when Fargo, a ship captain and rough sailor, met Zelbess the mermaid and married her. Fargo and Zelbess both propagated tolerance of humans and Demi-humans alike, and wanted the two groups to live in harmony. This dream was shattered when Zelbess was killed in Fargo's attempt to flee from the Acacia Dragoons during an incident in 1011 A.D.
The history of the Demi-humans then varied across the dimensions. In Another World, they maintained their hateful attitude well into 1020 A.D.; though they allowed humans in the village, they verbally abused any trespassers to discourage them from entering. In Home World, many Demi-humans were forced out of Marbule by the Black Dragon's nightmares, which manifested as transparent, haunting Lagoonates. They sought work aboard the S.S. Zelbess, commanded by Fargo; however, Fargo here exploited them for cheap labor. They lived in squalid conditions and undertook tireless work for him. This nearly destroyed centralized Demi-human civilization; however, rescue soon came in the form of the Magical Dreamers. Nikki sought out the Sage of Marbule, who taught him the Song of Marbule, the only tune capable of driving out the monsters of the Black Dragon. Fargo from Another World then came and taught Home Fargo a lesson, driving the ship to Marbule where the concert unfolded. The magnificent performance caused the nightmares of the Black Dragon to become corporeal, allowing their defeat at the hands of Serge. Marbule was subsequently refounded by humans and Demi-humans alike, who freely mingled and helped reconstruct the island. Many married at this time, ushering in a new era of peace between the two peoples.