Pre-SGW icon
Original Continuity

Black Arms
Form of Group and Statistics

Alien race



Resident location 

The Black Arms are a race of aliens who travel from world to world seeking to devour their native inhabitants. One world that they visited was Mobius, where their leader Black Doom made a deal with Gerald Robotnik to create Shadow the Hedgehog, who was intended to serve as the Black Arms' agent to prepare Mobius for their return 50 years later. However, they became embroiled in an interstellar war with another equally violent race, the Xorda, and thus were unable to return to Mobius for a time. The conflict raged across the entire galaxy and reduced at least one world, the Bem homeworld of Argentium, to a ruin of its former self.


50 Years Ago

Visiting Mobius fifty years prior to their conflict with the Xorda, the Black Arms laid plans for their eventual conquest. This involved placing an agent on the planet, for which they contacted Professor Gerald, the primary scientist aboard Space Colony ARK. Cutting a deal with the aliens, he used Black Arms genetic material—namely that of Black Doom himself—to create Shadow the Hedgehog, his Ultimate Life form. They then departed, intending to return and use a paralyzing toxin to render the inhabitants helpless so that they could consume them at their leisure. Learning that the Black Arms would return to Mobius in fifty years to conquer it, Gerald modified Shadow from his original purpose—that of developing a cure for Gerald's ill granddaughter, Maria Robotnik—to that of defending Mobius from the Black Arms upon their return. Shadow later learned this from Gerald's digital diary, and joined the Guardian Unit of Nations to prepare for their eventual return. (StH: #98, #171, #182, CSE)

War with the Xorda

See: Black Arms-Xorda War
Black Arms vs Xorda

The Black Arms fighting the Xorda over Argentium while Sonic and Knuckles watch.

The explanation for the delay in the Black Arms' return to Mobius was uncovered by Sonic the Hedgehog, Knuckles the Echidna, Miles "Tails" Prower, and Merlin Prower when they traveled to Argentium to rescue Amadeus Prower and his wife Rosemary, Tails' parents. As they were returning to feast on the population of Mobius, the Black Arms ran afoul of the Xorda aliens as both races desired to destroy Mobius for their own reasons. The resources diverted for the conflict prevented the Black Arms from following through with their plans for some time, while the violent conflict reduced countless worlds to wasteland. (StH: #170, CSE)

Notable Black Arms

Black Doom

Black Doom, the Arms' hive-mind.

  • Black Doom: The cruel hive-mind of the Black Arms who possesses Chaos Control abilities. He worked with Gerald Robotnik to create Shadow the Hedgehog, who was to be established as their agent on Mobius. Doom planned to return fifty years later to consume the populace, but he encountered the Xorda on his return trip and chose to enter war with them to prevent the former from denying his race their meal.
  • Shadow the Hedgehog: A Black Arms/hedgehog hybrid who was created by Gerald Robotnik and Black Doom. He possesses Black Doom's Chaos Control abilities. Originally intended to serve as the Black Arms agent to help them conquer Mobius, but after learning his true purpose vowed to destroy them if they ever returned.


Although they never physically appeared in the Pre-SGW Timeline (aside from Black Doom, who appears in Prof. Gerald's diary), it can be assumed that they would of resemble their video game counterparts. The shapes and sizes of Black Arms can vary widely, with multiple variants including humanoid, birdlike, and wormlike types, but in general they all possess grayish-green, brown, or black skin with crimson markings. Most have yellow or orange eyes without pupils. In general they don't wear any sort of clothing, with one of the sole exceptions being Black Doom, who wear robes.

Background Information

  • The Black Arms make their sole game appearance in the Shadow The Hedgehog video game. In the game, Shadow had to fight the Black Arms to prevent them from subjugating the earth. They have not appeared physically in any other game since, due to the circumstances at the end of the game.
  • Due to issues with Sega before the reboot, Ian Flynn said that Black Doom and the Black Arms would not be making a proper appearance until they were given the green-light to have them defeat the Xorda and come to Mobius. (1)