Master Core: ABIS is the only boss of Sonic Riders: Zero Gravity. Appearing in the last level, Mobius Strip, ABIS is formed by SCR-HD's transformation within Astral Babylon, twisted under the influence of the "Lightless Black" and the Arks of the Cosmos into this enraged giant. Determined to stop him before all of Sonic's world gets sucked into the evolving singularity, the heroes fly their Extreme Gear into the swirling ruins of Babylon Garden to take down the robot.
The Master Core rally is fought on a mobius-strip-shaped racecourse; Sonic pursues the retreating behemoth while ABIS hurls meteor storms and energy blasts into the track. The robot is also capable of initiating Gravity Drive, but Sonic can use this to boost forwards himself and smash into Master Core's rocky underside.
Six hits sees the robot being drawn into the black hole itself, destroying SCR-HD once and for all, as well as stopping the Lightless Black.
| Characters in the Sonic the Hedgehog game series
||Sonic (Super, Hyper, Darkspine, the Werehog, Excalibur) | Tails (Super) | Knuckles (Super, Hyper) | Amy Rose | Cream | Big | Blaze (Burning) | Emerl | Silver (Super) | Marine | Lumina Flowlight | Chip | Shahra | Knights of the Round Table | Caliburn | Yacker | Sticks | Avatar
||Shadow (Super) | Rouge | Espio | Charmy | Vector | Mighty | Ray | Chaos (Perfect) | E-102 Gamma | E-123 Omega | Bean | Bark | Jet | Wave | Storm | Shade | Merlina
||Dr. Eggman | Metal Sonic (Kai, Rocket, Neo, 3.0) | Mecha Sonic (Super) | Fang | Witchcart | Battle Kukku Army (15th, Speedy, Dr. Fukurokov) | Tails Doll | Metal Knuckles | E-Series | ZERO | Void | Biolizard | Gemerl | Eggman Nega | Black Doom | Angelus | Iblis | Mephiles | Solaris | Erazor Djinn | Captain Whisker | Johnny | Master Core: ABIS | Ix (Super) | Dark Gaia | King Arthur | Orbot | Cubot | Deadly Six (Zavok, Zazz, Zomom, Master Zik, Zeena, Zor) | Hard-Boiled Heavies | Infinite
|| Sonic/Heroes | Rose | Dark | Chaotix | Babylon
|| Gerald & Maria Robotnik | Froggy | Chao | Omochao | Cheese | Chocola | Vanilla | Tikal | Pachacamac | E-101 Beta | Illumina | President | G.U.N. Commander | Elise | Duke of Soleanna | Coconut Crew | Vikings | Professor Pickle | Wentos | Don Fachio | Heavy and Bomb | Tiara Boobowski | Honey | Flicky | Animals | Wisps