Chaos Emeralds

The Chaos Emeralds (カオス エメラルド) are seven fictional gemstones from the Sonic the Hedgehog video games. The Chaos Emeralds have mystical properties and abilities, and the holder of them all can use them for a variety of purposes, including transforming into a powerful "super form". Each emerald is an everlasting source of energy and is capable of floating in the air on its own power. The emeralds are commonly and traditionally collected within a Special Stage. While they were more like "bonus" items in the early games of the series, the Chaos Emeralds became necessary plot devices in Sonic Adventure, and that trend has continued throughout the later 3D games.

Game Background
In the original Sega release of Sonic The Hedgehog there were only six Chaos Emeralds and when they were all collected they gave the player no special abilities, disappearing at the games end. When sega released Sonic the Hedgehog 2 they became the The Seven Chaos Emeralds and if the player collected them all as Sonic he could achieve a super form. Sonic the Hedgehog 3 changed the color sceme of the emeralds slightly and  altered their shape. During Sonic & Knuckles the players could collect a set of 14 emeralds transforming the original seven into super emeralds ganting Sonic the ability to transform into Hyper Sonic while Tails and Knuckles could only achieve a standard super form.

Other Sonic games have also had many different character oriented abilities and also many varying shapes and colors usually going with a common theme.

The Chaos Emeralds in themselves are usually used to power machines, for weapons of mass destruction, Chaos powers, and activating Super Transformation. The energy can also be given from one super form to another character to allow that person to achieve a super form of his own, as seen at the end of Sonic Heroes and Sonic the Hedgehog (2006). And some cutscenes and gameplay times have shown that accessing their powers is possible without being in direct possession of an Emerald, the user is merely required to be close to one or more of them. .

The 7 Emeralds and the Super Sonic transformation were widely viewed as a homage to Dragon Ball Z and the Super Saiyan transformations within. When asked if comments about this were received from Dragon Ball creator Akira Toriyama, former Sega executive producer Yuji Naka smiled and said no.

Role in the games
Throughout most of the early games, Doctor Eggman tries to obtain the Chaos Emeralds in order to fuel his doomsday weapons. The player can choose to collect the Emeralds in their Special Stages in order to unlock a "good ending", a super form, or both.

In Sonic Adventure, the Chaos Emeralds were collected by Eggman in order to feed Chaos, the former guardian of the Chao and Emeralds, who can change its form every time it received one of the gems. With all seven, it became Perfect Chaos, and used up all of the negative energy in all seven Emeralds before dropping the unpowered and colorless Emeralds onto the ground. Sonic then picked up all seven emeralds and used the positive energy to become Super Sonic and neutralize Perfect Chaos.

In Sonic Adventure 2, Sonic and Shadow had the ability to use the Chaos Emeralds to utilize "Chaos Control", an ability that alters time and space to teleport or freeze time. (However, Sonic didn't know that he could use Chaos Control until he absolutely had to in order to save himself from a sticky situation; furthermore, Sonic managed to use the ability with a fake emerald.)

In Sonic Rivals, Silver has returned and does not remember anyone; just that he is once again trying to save the world from Eggman Nega. Eggman Nega has a camera that seems to have the power of a Chaos Emerald. The camera locks a person/character in a card and freezes time for that person. The cards give off almost the same power of the Chaos Emeralds, like they are an unending power source.

In Sonic Heroes, Sonic becomes Super Sonic, and allows Tails and Knuckles to use the Chaos Emerald energy to transform into imitations of their super forms, the only visual changes being two spheres of golden energy surrounding Tails and Knuckles.

In Shadow the Hedgehog, the Emeralds were found throughout the stages again (except this time, they're obtained by beating the stage they're in), and Shadow used their miraculous powers to slowly reassemble his memories with each emerald. Shadow collected all seven by the end of the game, only to let them be stolen by the evil alien Black Doom, who used them to warp the Black Comet to Earth's surface with Chaos Control. Shadow then used the chaos emeralds to transform in Super Shadow to defeat Black Doom.

In the 2006 game Sonic the Hedgehog the Emeralds fully take on the power to "transform thoughts into power", just as the Master Emerald was said to be capable of doing in Sonic Adventure.

It has been hinted in Sonic Rush Adventure that the Chaos Emeralds have the ability to think and are capable of decision. They also seem to want to aid Sonic and others which is why they remain stable around the characters.

In Super Smash Bros. Brawl, the Chaos Emeralds appear as part of Sonic's Final Smash. He also holds a Blue Chaos Emerald during one of his victory shots.

Amount
In the first game of the series, Sonic the Hedgehog, there were six Chaos Emeralds. This was also true for the Game Gear/Master System games Sonic the Hedgehog, Sonic the Hedgehog 2, Sonic Chaos and Tails Adventure. The amount was extended to seven Emeralds in Sonic the Hedgehog 2 for the Mega Drive, and that number has been consistent ever since, with three exceptions. Sonic Spinball features 16 emeralds. An eighth, golden Emerald can be found in Sonic the Hedgehog 3 by entering a code at the Sound Test and can not be seen normally, except by a debug mode glitch in the locked on version where trying to jump on a Super Emerald after using debug mode to bypass the fight with Knuckles gives you access to the golden Super Emerald. Sonic the Fighters features eight Emeralds as part of the story; in order to travel to the Death Egg II, the player must collect all the Chaos Emeralds by defeating the eight characters that hold them. The widely accepted reason for this is because there are eight fighters, and so Sega-AM2 added another Chaos Emerald. In Adventures of Sonic the Hedgehog, Chaos Emeralds were part of a major plot in the Quest for the Chaos Emeralds saga. Robotnik, Scratch and Grounder stole Prof. Caninestein's time machine to travel back in time to steal four Chaos Emeralds, each with a unique power. One has the power to grant its bearer immortality, another grants invulnerability, another has the power to make people and things invisible, and the last one can bring inanimate things (and maybe even dead people) to life. Anyone who harnesses the power of all four jewels becomes an all-powerful god. Robotnik did just that, and Sonic and Tails had to bring all of their past selves to stop him. In the SatAm series, Chaos Emeralds have made no appearances whatsoever. Although, there were equally powerful items like the Deep Power Stones that made Sonic and Princess Sally go super. In Sonic Underground, a Chaos Emerald holds Knuckles the Echidna's homeland, the Floating Island afloat. In the anime Sonic X, Sonic and his friends recover the lost Chaos Emeralds (it should be noted that in the anime, when an electrical object is near a chaos emerald it goes haywire). Unlike the three American animated shows, Sonic uses the jewels to become Super Sonic. In the anime film Sonic the Hedgehog: The Movie, Chaos Emeralds once again made no appearance, and neither did Power Rings.

Colors
The colors of the Chaos Emeralds are nowadays red, blue, yellow, green, white/grey, cyan, and purple. These are also the seven components of the RGB color model. This has not always been the case.

In the original Sonic the Hedgehog, the six Emeralds were blue, yellow, red, green, pink and gray. A seventh, purple Emerald was added to the roster in Sonic the Hedgehog 2, after which Sonic the Hedgehog 3 replaced the pink emerald with a cyan one, and the yellow Emerald with an orange one. The orange Emerald was reverted back to yellow again in Sonic Adventure, and the colors of the Emeralds have remained essentially constant ever since. with the grey emerald sometimes being rendered as white. It was revealed in Sonic Adventure that the negative energy within the Emeralds gives them their colors, as after Chaos used the Emerald's energy to become Perfect Chaos the emeralds are shown to be clear.

Certain games have used their own unique colors for the emeralds. In Sonic Spinball, they are all blue. In Sonic Battle, they are all green. In Sonic R, the Blue Emerald is absent, replaced with an orange one.

In the Sonic the Hedgehog comic series by Archie Comics, the emeralds were spread across seven locations in the galaxy and there were hundreds of them. Each location had its own unique emerald color, with the total number of colors being seven. A later plot development led to all Emeralds of a certain color being fused together as one, resulting in the seven emeralds of the games. A black emerald served as a prison for Chaos 0 (see Sonic the Hedgehog #80), but it is not specifically stated to be a chaos emerald.

In the Sonic the Comic series, the emeralds are blue, yellow, red, green, orange, grey and purple.

Power source
As revealed in Sonic Adventure, Chaos Emeralds have both positive energy and negative energy. The negative energy is accessed by negative feelings while the positive energy is harnessed/activated by friendship, as revealed when Tails says, "Negative forces aren't the only way to empower the Chaos Emeralds. Our positive feelings toward each other can make them work!" Also, in Sonic Rush, Sonic told Blaze that realizing her feelings to her friends would help make the Emeralds work. However, it is shown that the negative energies of the Chaos Emeralds are what gives them their color (As seen in Sonic Adventure and Sonic Rush).

Although the Emeralds are described as having unlimited energy, which is why they are often sought after by other characters, having all seven allows the energy to be tapped into more efficiently, as seen in Sonic Adventure 2, after the ARK's Eclipse Cannon was fired with six emeralds, it was described as taking far too long to charge back up without the seventh. . Despite destroying a good portion of the moon by harnessing six emeralds, the Eclipse Cannon was only able to destroy a large city by using five Emeralds.

Super transformation
Super transformation is a frequently recurring gameplay feature and story element that allows the player to play as a powered up version of the character, traditionally obtained by collecting all of the Chaos Emeralds in addition to 50 Rings, as was the case in the Genesis games starting with Sonic the Hedgehog 2. The player can also collect the Sol Emeralds, activate the Super Emeralds, or break open an Item box with an "S" on it.

Features
Super transformation generally gives the character enhanced speed, similar to using a "High Speed" power up. The transformation also originally gave the character the same effect as the "Invincible" power up. As of Sonic & Knuckles (and all games since), taking damage while using super transformation will result in the character being thrown back a small distance. Even with the transformation enabled, during gameplay the character can still die by falling in a bottomless pit, being crushed, or drowning. Also, in Sonic the Hedgehog (2006 release), Solaris is capable of damaging Sonic even when under super transformation.

The compromise in super transformation is that the power is sustained by Rings during gameplay. It originally took 50 Rings to enable the transformation, which are then gradually drained over time. Starting with Sonic Adventure, players are no longer allowed to manually transform, but are simply given the ability through the story. The rings are only used as a gameplay mechanic to limit how long the form can last. The exception to this was Sonic Riders, where only one Ring is needed. Running out of Rings in a final boss battle results in an instant loss of a life, usually due to the character being in unsurvivable conditions such as over a flooded city street, in the cold of space or the magma filled core of a planet.

Another general super transformation ability is flight. This was originally unique to Super Sonic as he would fly above the ground at maximum speed, and take to full flight at the end of Sonic the Hedgehog 2. The ability is now shared by all transformations and is a defining trait. A character can also hover in midair as, beginning with Sonic Adventure 2, the transformation is usually used in areas high above the ground. The air can also act as the ground as shown in Sonic Heroes, enabling the player to use the same controls as if in a regular level.

Although it is a power up in itself, the super transformation can be powered up further. To do this, the player must collect all seven of the Chaos Emeralds and reactivate them in their powered up state as the "Super Emeralds." Once transformed, the character will then leave afterimages in its wake and be given an ability to instantly kill all enemies on screen (excluding boss battles). This was seen only in Sonic the Hedgehog 3 & Knuckles.

If multiple people are around when the chaos emeralds are being used they can both enter "Super Form" (such as Sonic Adventure 2 Battle, Sonic Heroes, and the 2006 Sonic the Hedgehog), however, even though there can be multiple users, they share the same amount of rings that keeps them in "Super Form".

Chaos Control
Although Shadow the Hedgehog is the first to be seen using Chaos Control in Sonic Adventure 2, the earliest known user of the ability is Black Doom, the Black Arms leader, as he could very well be over 2000 years old (as he states before the "Sky Troops" stage in Shadow the Hedgehog that he visited Earth around that time years ago). Black Doom demonstrated that he could use Chaos Control by teleporting the Black Comet, the Black Arms homeworld, down to the surface of Earth. In the Shadow the Hedgehog game, Chaos Control is described as being enhanced with each Chaos Emerald added to its usage, until reaching full power with all 7 Emeralds.

Its use in the games has been inconsistent. Although cutscenes and official bios often claim that the Chaos Emeralds allow the use of Chaos Control, Shadow the Hedgehog has used it several times during gameplay and a few cutscenes without a visible Emerald, such as in Sonic Rivals and Sonic Battle. Sonic Adventure 2 further explained that Chaos Control is also possible with a fake Emerald which has the same wavelength and properties.

The Sonic the Hedgehog Comic series takes a more consistent approach. According to Knuckles, Guardians have the ability to tap into the "Chaos Force" to use techniques like Chaos Control without a Chaos Emerald. However, Shadow is able to use Chaos Control without an Emerald, thus the Ultimate Lifeform can be included among them.

Other Chaos Powers
Appearing first in the 2-player mode of Sonic Adventure 2 and then canonized in the final level of Shadow the Hedgehog and Sonic X, Chaos Spear is an attack whereby bolts of energy are thrown at an opponent. Another related power, that first appeared in the game Shadow the Hedgehog, is Chaos Blast. It is a large explosion of energy radiating outward from its creator. These powers have been altered and expanded upon with game-specific abilities by subsequent video games.

Master Emerald
The Master Emerald (マスー エメラルド) is a large, green emerald. It has unbound power, and is used to keep the Angel Island afloat in the sky. The Master Emerald also has the power to fully control everything that the Chaos Emeralds do, as according to the ancient saying from Sonic Adventure: "The servers are the 7 Chaos. Chaos is power, power enriched by the heart. The controller is the one that unifies the chaos." The Master Emerald also possesses the ability to both negate and empower the Chaos Emeralds, meaning it can stop the energy of the Chaos Emeralds, or enhance them, as seen in Sonic Adventure 2 and Sonic 3 & Knuckles, respectively. Only descendants of Knuckles the Echidna's tribe are capable of controlling it. Although, in Sonic & Knuckles, Mecha Sonic also absorbed its energy to obtain an enhanced form very similar to Super Sonic.

The Master Emerald can be shattered into any number of pieces, but can always be put back together flawlessly, with no loss of power.

Guardians
The Chaos Emeralds were originally guarded by Chaos, a mutated chao that protected both the Emerald Shrine and the other Chao that lived there.

Tikal found Chaos and the Chao in her ancient Echidna tribe. She loved them and cared for them, but her father found out about them and wanted the power of the Emeralds for himself. He attacked the Emerald Shrine and tried to steal the gems, but Chaos absorbed the negative power of the Emeralds, became Perfect Chaos, and destroyed the majority of the Echidna tribe. Tikal appealed to the Master Emerald to seal Chaos away inside it, sealing her own consciousness in the process. The Chao lived on and bred, however. This is the point at which the Echidnas took over in protecting the Emeralds. Knuckles is the Echidna that protects them in the time of the current Sonic the Hedgehog time line, and also the only Echidna left according to the Sonic the Hedgehog 3 manual (in the Sonic Team storyline, other continuities like the American Sonic comics have more echidnas in existence).