All of you ungrateful humans, who took everything away from me, will feel my loss and despair!
~ Professor Gerald Robotnik
The countdown marking my final revenge on this world has begun! In a few minutes, you will be destroyed! Soon, Space Colony ARK will hurtle through the atmosphere and crash into this world with cataclysmic force!
~ Professor Gerald Robotnik in Sonic X.

Professor Gerald Robotnik (simply known as Gerald Robotnik) is a brilliant but tragic scientist who is the late grandfather of both the late Maria Robotnik and Doctor Eggman, who also serves as the main antagonist in the videogame Sonic Adventure 2. He also appears as the posthumous antagonist of the Shadow Saga in the TV show Sonic X, which is loosely based on Sonic Adventure 2's story.


Many years ago, Gerald Robotnik was offered a position as a researcher onboard the Space Colony ARK by the United Federation. While he initially refused, he later accepted in hopes of curing his granddaughter Maria of her fatal illness. His goal was to create "The Ultimate Lifeform", a being that could live forever. Many researchers did not believe it to be possible, and began to name to project 'Project Shadow' due to it's apparently unreachable goal, as well as the level of secrecy the project required. Gerald liked the name, and it stuck.

Professor Robotnik's initial experiments involved lizards, due to their ability to regenerate limbs. The result was the Biolizard, a mutant lizard prototype that proved to be unstable, requiring a life support system to survive. However, the prototype was deemed a failure and too dangerous, so it was sealed in the core of the colony.

Some time later, Professor Robotnik came in contact with the extraterrestrial Black Doom, and, using his DNA, created Shadow the Hedgehog. Upon learning that Black Doom and the Black Arms race wished to harvest the human race as food, Professor Robotnik secretly developed the Eclipse Cannon in order to destroy them the next time they visited Earth.

However, the government soon concluded that Gerald's experiments were dangerous to humanity, and sent GUN to the ARK to neutralize them. Gerald managed to escape, but was immediately captured by the government and sent to Prison Island, where he was forced to continue his experiments. GUN later managed to capture Shadow and sent him to Gerald, who discovered that Maria was among the casualties of the raid, and was stricken with grief over how his own research claimed the life his beloved granddaughter. Losing his will to live, he was driven insane, and became obsessed with exacting revenge on humanity. He made plans to send the ARK colliding with the Earth and destroy the planet once the 7 Chaos Emeralds were collected, programming Shadow and the Biolizard to ensure his plan's success. Unfortunately for Professor Robotnik, the government feared that Gerald would soon retaliate and had him executed, but not before the mad scientist left one final recording of his execution, in which he explained his plans for revenge.

Sonic X

Prof. Gerald Robotnik also makes an appearance as the true antagonist in the Shadow Saga in the animated TV series Sonic X. His story is very similar towards the story in Sonic Adventure 2, but with some differences. Some differences include; being unclear if Gerald Robotnik came in contact with Black Doom to create Shadow the Hedgehog.



  • In the photograph of him and Maria on Sonic Adventure 2, he was skinnier than his grandson. However, in the photograph of him and Maria on Shadow the Hedgehog, he is shown to be much bigger.
    • Also, his glasses on the photograph in Sonic Adventure 2 are smaller, but on Shadow the Hedgehog, they are bigger and take up nearly twice the space.
  • There seems to be a continuity error involving Gerald. G.U.N. raided the ARK to either kill or imprison everyone onboard. They somehow captured Shadow on Earth, but on the day of the raid, Gerald is imprisoned and stripped of all use of money and technology. This makes it impossible for him to record his motives on his diary, reprogram the ARK to fall to Earth, reprogram Shadow's brain to think he has to destroy the world, or produce a 50-year-old video of his own execution. It could be that he hid from G.U.N. and lives through the raid and updated his diary and reprogrammed the ARK when the troopers left, then got captured again, or he could have been reprogramming the ARK while G.U.N. was attacking, or he had escaped imprisonment and got to the ARK, but arrested again and executed when he was done.