The Black Arms are a demonic alien race led by Black Doom. They appear in the game Shadow the Hedgehog, in which they invade Earth in search of the seven Chaos Emeralds, and are opposed (or aided) by Shadow the Hedgehog and other characters. They are commonly referred to as "the black creatures", "black aliens" or even "terrorists" as the inhabitants of Earth do not know their real name (though Tails refers to them by name in one instance), and easily recognized by their black-and-red skin pigmentation.
The Black Arms are out to collect the Chaos Emeralds so that they can use Chaos Control to teleport their Black Comet to the Earth's surface, where it digs into the planet and releases a toxic gas that paralyzes all life (except those with Black Arms DNA). It is unknown what the Black Arms plan to do with Earth after conquering it. The Black Arms launch a surprise invasion of Earth in the beginning of Shadow the Hedgehog, and destroy everything in their way while searching for the Chaos Emeralds. They are immediately opposed by Sonic the Hedgehog and his friends, the military organization GUN bent on protecting the planet, and even Doctor Eggman, who is usually the antagonist in the Sonic games. Throughout the game, the player controls Shadow the Hedgehog, and can choose whether to help the Black Arms with their invasion, or to defend the Earth along with the other characters. No matter what the player chooses to do, the game has a "final ending", where Black Doom obtains the Chaos Emeralds and warps the Black Comet to the planet's surface, where it digs into the planet and releases a toxic gas that paralyzes all life without Black Arms DNA. Shadow opposes the Black Arms and becomes Super Shadow. He defeats Devil Doom, a powerful mutated form of Black Doom, and proceeds to use Chaos Control to send the Black Comet into space again. Then he blasts it with the Eclipse Cannon on the Space Colony ARK, destroying it along with the remaining Black Arms residing inside it.The Black Arms are now assumed to be extinct, with Shadow himself being the last member of their species through blood.
Black Doom is the evil overlord of the Black Arms, and the only one shown with the ability to speak the human language. He has three eyes and seems to float above the ground, wearing a cloak with metal ornaments. He helped Gerald Robotnik create Shadow the Hedgehog, by using his own blood. He has lived for over 2000 years, and planned to use the human beings as an "energy source", possibly food for his larvae. He was eventually defeated by Shadow. Black Doom can separate from one of his eyes, transforming it into a tentacled entity known as Doom's Eye that serves to do his bidding.
Black Arms Variants
These are the members of the alien race that invade earth under Black Doom's command. They will attack Shadow, even if Shadow is attempting to complete one of Black Doom's missions. Members of the Black Arms include the Black Warriors, Black Oaks and Black Arms Annelids. The following is a list of creatures in the Black Arms.
The Death Leeches are described by Black Doom as the Black Arms' offspring. They are pulsating dark red blobs with 3 horns positioned around an eye in the middle of their bodies. They are capable of sticking to walls, and are blood-suckers. They have no endurance, and are always killed with one hit, regardless of the weapon.
The Black Warriors are the most common Black Arms aliens in the game. They are roughly human sized (just a little bigger than an average GUN soldier) and carry various Black Arms weapons (lasers, swords, shields, etc.). It usually requires two shots from most weapons to kill them.
The Black Oaks are giant Black Arms soldiers. According to Doom's Eye, the Black Oaks are "heralded for their pure strength" (they can easily swat aside cars), and form the backbone of the Black Arms army. They have high endurance, but also are slow moving. They carry large swords and occasionally alien rocket launchers and clubs. They take anywhere from two to seven shots to defeat although the ones that carry clubs are able to block attacks from projectile weapons with their hands. As with all enemies, they can be defeated in one shot with the Shadow Rifle.
Black Arms Annelids
The Black Arms Annelids are giant worms. They burrow underground and attack from beneath, using smaller worms that home in on their prey. According to Doom's Eye, the worms find their prey by detecting their target's vital signs. The most common Annelids are called Sand Worms. There are also Annelids unique to certain areas such as Death Worms and Gold Worms (see below for Gold Worms in Gold Annelids). The Black Arms annelids share many characteristics of the Biolizard, such as their impregnable skin, coloring and texture, methods of attack, and sounds they make as they surface. Like the Oaks, it takes from two to seven hits to destroy them. Interestingly, both types of Annelids can easily be sucked up by a vacuum weapon, making them easy to defeat when using the Egg Vacuum weapon.
The Gold Annelids are stronger, golden Black Arm Annelids. They appear only on the stages The Last Way and Black Comet. They are stronger and faster than regular annelids and are harder to kill. Gold Annelids are invincible to some of the weaker weapons in the game.
The Killer Plant is a giant moving plant lifeform, which judging from its resemblance to earth flowers, was probably mutated by the Black Arms. It can breathe fire and extend its branches. Once defeated, it will temporarily shrink into a harmless bud, but it will revive again if given enough time. No points are awarded for killing it.
The Black Wing is a small bat-like creature similar to Black Hawks. They have little endurance and are almost always killed with one hit.
The Black Hawks are small winged dragons which are much stronger then the Black Wings. They are capable of firing blue energy waves and flying unhindered in space. In some cases, when they are weakened, Shadow can ride on their backs.
Black Volts are Black Hawks that have gold armor plating and are equipped with Worm Shooters. Due to their armor, they have more endurance than normal Black Hawks. It is also possible that Black Volts are Black Hawk-shaped robots, due to the name "volt."
Black Assassins (aka Elite Soldiers)
The Black Assassins only appear in the stages Black Comet, Final Haunt, and The Last Way. They look like armored Black Arms Soldiers, but they can withstand many attacks and have the ability to disappear and reappear at will. They are all armed with Refractors.
The Black Bull is a powerful creature in the Black Arms. It resembles a cross between a giant maggot and a dragon. Due to its large blubbery body, its only weak spot is its single green eye. It can breathe fire and can produce Black Wings from its mouth. It appears as a boss after the completion of the Lethal Highway and/or Death Ruins stages. Like the Blue Falcon, this boss was named after a machine from the F-Zero series; in this instance, Black Shadow's machine, the Black Bull. This is obvious, because SEGA co-developed F-Zero GX/AX.
Although not necessarily part of the Black Arms army, the Black Fruit (unofficial name) are probably from their home planet. They have a short stalk, with a large spherical bulb on top. It is mostly red, and translucent, as a slight yellow glow can be seen from within. Spikes grow from the bulb, giving Shadow damage if he touches it. They can easily be destroyed in a single hit.
Shadow the Hedgehog
In theory, Shadow is part Black Arms alien because of his creation from Black Doom's blood. However, he is not a part of their army; rather, he a secret weapon, although he did not know this fact himself until the final story in Shadow the Hedgehog. Shadow's efforts have finally put an end to the Black Arms' reign of terror.
Black Arms Weaponry
Black Sword: Big purple sword. Sometimes accompanied by a shield.
Dark Hammer: Large blue hammer-like weapons used by some Black Arm Oaks.
Black Shield: Small transparent shield that is very resistant to projectiles. Large stationary shields can be found on the Black Comet, but they are much weaker.
Light Shot: Basic plasma machine gun pistol used by most Black Arm infantry.
Flash Shot: Plasma guns that are a common sight among Black Arms.
Ring Shot: Gun that shoots slow pink energy rings, similar to the shots from the turtle enemies in Sonic Heroes.
Splitter: Broad gun that fires fast red energy discs. The shots act like laser shots as they can shoot through multiple enemies and bounce off walls.
Worm Shooter: Weapon that locks onto targets, and fires small homing explosive worms at the targets.
Black Barrel: Powerful bazooka-like weapon that fires exploding energy shots. The same technology is used in the Black Cannons. A more powerful variant of this weapon exists, different in color and slightly in shape.
Black Cannon: Powerful stationary alien turret that can be used to destroy things such as ships. They have a Black Barrel on their tip, and fire the same shots. Once destroyed, they leave a Black Barrel for Shadow to pick up.
Refractor: Laser rifle that fires red lasers that bounce off walls. All Black Assassins are armed with this weapon.
Heavy Shot: Machine-gun rifle similar to the light shot, but larger, more powerful, and with a different sound effect. Seen in "Black Comet" and possibly the other two levels in the Black Comet.
Vacuum Pod: Odd weapon that sucks objects into its muzzle and and compresses them into small balls that can be fired at enemies, similar to Sonic's magic hand attack from Sonic Adventure 2 Battle. It can also suck in rings without using up ammo. Enemies use this weapon by sucking shadow in to touch them. Flying enemies cannot be sucked in, and neither can enemies too large. While stationary, it can be seen slowly breathing.
Bombs: Purple explosives used by the Black Arms, the largest of which is the "city annihilator" bomb, which, when a number of them are placed strategically, can destroy an entire city.
Satellite Laser: Large energy beams coming down from the sky. Most likely fired from warships or the Black Comet itself. There is also an unlockable weapon by the same name which launches down a laser strike from the sky directly on the targeted enemy, making it more of a remote than a weapon.
Biological weapons used during Black Doom's assault. Some of these weapons are gases able to turn an individual good or evil. Others can, upon entering the bloodstream of a non-Black Arm, cause total paralysis, though the effect is only temporary, as the main characters were infected with it, but managed to break free after a few minutes.
Black Arms Vehicles
Air Saucers: One-manned floating discs that can be used to cross hazardous surfaces, such as toxic water. Upon analyzing one, E-123 Omega is astounded that it floats without using either fuel or engine components.
Black Tank: A powerful Black Arms Tank that appears in the Lethal Highway stage and somewhat resembles a stealth bomber. The tank is surrounded by a shield that can withstand many attacks, but it is oddly enough unarmed, possibly it is not a tank but simply some kind of armored troop transport for the Black Arms. Destroying it is the Hero mission on Lethal Highway and the best way to defeat it is using a rapid-fire weapon, preferably from the Black Arms. The most effective weapon is the Shadow Rifle and the Gatling gun which can be obtained behind the five-key door, with the maximum of 40 ammo can easily take out the tank in below 10 seconds. Interestingly, Sonic claims that guns are ineffective against the Black Tank, (despite the fact that it is easily able to be taken down by guns, though he may have talking about when the shield was up).
Gunships: Large organic-looking battleships. They usually appear in the Black Comet, Final Haunt and the Last Way stages. Gunships are armed with a Black Cannon and can spawn enemies. The best way to attack these ships is to use nearby cannons or the shadow rifle.
Black Arms Strongholds
The Black Comet is a massive comet that passes by the Earth every 50 years. It is the home and/or a mode of transportation for the Black Arms. The comet itself appears to be alive or techno-organic in nature, most notably when it was teleported to Earth and seemed to take on a life of its own to dig into the surface. When inside, it is almost like being in the body of a living organism. There are pulsating growths and what appear to be tentacles, organs and throat-like halls and many organic sounds. For example, in the Japanese version of the game, when the tentacles are destroyed, a roar (very similar to the Biolizard's) can be heard. There is a vicious substance in the comet that only death leeches and worms can exist in. Even Black Doom continuously warns Shadow that "that toxic substance is fatal". The tentacle-like projections also appear to exist in the substance. The last time the comet passed by Earth, Black Doom made a pact with Gerald Robotnik in order to create the Ultimate Lifeform, Shadow the Hedgehog. Shadow would help Gerald in his research and Black Doom in his quest to collect the 7 Chaos Emeralds. Gerald, however, designed the Eclipse Cannon to destroy the Black Comet when it returned. 50 years later, as the Black Comet approached Earth during the start of Shadow the Hedgehog, the aliens began the final phase of their mission to collect the 7 Chaos Emeralds and enslave the humans. The Black Comet did not have enough speed to make it to Earth's surface on its own, so Black Doom uses the power of the Chaos Emeralds to teleport the comet to Earth. However, Black Doom's plans were foiled when Shadow teleported it back into space and used the Eclipse Cannon to destroy the Black Comet and all of the Black Arms inside of it. It is interesting to note that while the Pure Hero level Final Haunt, the Black Comet (predictably) is full of Black Arms, on the Semi-Dark final level Black Comet, it is full of Gun Robots, and there are few (if any), Black Arms present.
Black Doom transported a long complex of temples to the Glyphic Canyon 2000 years prior to the games (notably, from a scientific perspective, all the planets were lined up at zero point 2000 years ago). According to Black Doom, it is the Black Arm's holy ground. These bird-shaped ruins were sealed away and deactivated many years ago. In order to reawaken this temple, one must touch the five large jewels within in it. "Reawakening" the temple makes it airborne, with the various pieces being held together with red laser-looking beams. If one destroys the jewels after this, the temples lose their power and fall down to the earth again. Activating the jewels for Black Doom is the Dark mission for the "Glyphic Canyon" stage, while destroying them is the Hero mission for the "Sky Troops" stage, where Dr. Eggman battles the flying ruins with his Eggman Fleet. The temple is automatically reawakened when Shadow reaches Sky Troops, regardless of whether or not he has personally touched the five jewels, suggesting that the "evil path" through Glyphic Canyon is the canon route, or that the Black Arms activate the jewels themselves if Shadow does not do it for them. There are also large tornado-like whirlwinds and dust storms in the ruins, that according to Black Doom were set in motion to stop humans from accessing them.