Orbix Xaxis is the main antagonist of books nine, ten and eleven of Paul Stewart and Chris Riddell's The Edge Chronicles. He has seized control of the world of the Edge during a vicious time of upheavel and chaos caused by the onset of the Stone sickness (which is actually due to the Gloamglozer cursing the Edge but has sent every inhabitant of the Edge into factions over its origin).
Orbix Xaxis lived in Old Sanctaphrax and he studied the Sky along with several other scholars who were called Sky Scholars. Those who studied the Deepwoods and the earthly terrain of the Edge were called Earth Scholars. When the new Most High Academe (a youth named Cowlquape Pentaphraxis) was usurped from his position by a villain named Vox Verlix, who took the office for himself, Orbix Xaxis and the Sky Scholars were given high positions in the new government. (Cowlquape had learned that the Mother Storm, the Edge's creator, was returning and Sanctaphrax, being a floating city, would destroy the Edge by blocking the Storm, so the city had to be unchained and he had severed the chain to the anger of the old inhabitants, but a new rock had grown for a new city to be built upon.) Vox Verlix immediately began building a new Sanctaphrax, a single tower upon the rock of Sanctaphrax called the Tower of Night.
Orbix Xaxis betrayed Vox, however, when he became ambitious, greedy and cruel and took the Tower from Vox and kicked him out into Undertown, the capital of the Edge. Vox ran away to the Librarians, a branch of the Earth Scholars, but Orbix hated the Earth Scholars and plotted their downfall. He then launched his Sky Scholars upon the Librarians and slaughtered half of them and Vox ran away to his old Palace of Statues upon this attack. Vox hid in the Palace for the rest of his life, becoming obese as he did so from confinement, and ironically, although Orbix Xaxis captured many Librarians (including Cowlquape) and imprisoned them in the dungeons of the Tower of Night, Cowlquape believed the real prisoner was his enemy Vox.
Orbix Xaxis was now secure as a ruler of the Edge (aside from the goblin leader General Tytugg, who ruled Undertown, and the shryke leader Mother Muleclaw) and he plotted to finally destroy the surviving Librarians. The Librarians would patrol Undertown's skies in their sky craft, but Orbix, in his Tower, would shoot them down and then send his Sky Scholars (now called the Guardians of Night) out to Undertown to capture them and he would have his chief interrogator, Xanth Filatine, to question them and then Orbix Xaxis would feed the Librarians to his Rock Demons, bat-like creatures who lived in the crevices and fissures of Undertown.
This way of life continued for the evil Orbix Xaxis and his Guardians for years, until three new Librarians, Rook Barkwater, Stob Lummus and Magda Burlix, were chosen as candidates to go to the Deepwoods and become Librarian Knights. To Orbix Xaxis' surprise, Xanth Filatine volunteered to go and capture all the elect, and Xanth did go to the Deepwoods and train as a Librarian, giving him a taste of the "enemy." But he geniunely grew to like the Librarians and he felt free, much freer in the Deepwoods than in the Tower of Night. Soon, Xanth's guilt grew and he had to run back to Undertown rather than risk being imprisoned himself. He returned to Orbix Xaxis in the Tower yet the Guardians no longer believed Xanth was one of them and became suspicious of him.
Rook Barkwater returned to the Tower to free Cowlquape and Cowlquape was finally free again.
Orbix Xaxis personally killed the sky pirate captain Twig, whom Rook was travelling with and whom Cowlquape was an old friend of, but he was not in the least deterred about Cowlquape's escape; in fact, Orbix used Cowlquape's cell for more Librarian prisoners. He and his Guardians gathered on the gantries every night to look for a Storm, and Orbix Xaxis kept seeing Vox's fireballs being launched into the sky. He knew a Storm was on its way.
One fireball knocked Rook out of the air and destroyed his skycraft; yet he made it out, only to be captured by goblins and made Vox's kitchen slave. Cowlquape paid Vox a visit and ordered Rook free. Vox told Cowlquape there would be a Storm coming and told the Librarians to evacuate Undertown and go to the Deepwoods. Vox pleaded to be taken with them.
Magda Burlix had gone looking for Rook when he crashed and Xanth captured her. He interrogated her under Orbix Xaxis' supervision and then Orbix knew that Xanth was indeed a Guardian. He asked him to go up to the top of the Tower and oil the conductor called Midnight's Spike for the Storm. Xanth actually stole the deadbolt for the conductor and escaped with Magda, yet they were captured and Orbix was angered, and fed them to the Rock Demons with the intentions of the demons running into the Librarian sewers and eating everyone there; yet the Librarians had evacuated. Xanth and Magda got out OK without being chased by the Rock Demons; and a massive Storm did finally arrive, exciting Orbix, and yet, when the conductor was raised, Orbix Xaxis found he could not lift it due to the deadbolt being gone. He got enraged; and jumped up on the top of the Tower to try and be a human conduit for the Storm, which actually vaporized him.
- He is presumed to be descended from Daxiel Xaxis, the villain of The Winter Knights.