Master Emerald

The Master Emerald (マスターエメラルド) is an object that appears in the Sonic the Hedgehog series. It is a large, green emerald and a mystical relic from the untold past, and stands as a prominent object in the world due to its immeasurable power and its ability to control the Chaos Emeralds. It rests on Angel Island where its power keeps the island floating in the sky. Over the millennia, the Master Emerald has been guarded by the surviving Echidnas of the Knuckles Clan, with its current guardian being Knuckles the Echidna.

Background
Little is known about the origin of the Master Emerald, as the time of its creation predates any recorded history in the world. According to what little knowledge there exist, the Master Emerald was created by the gods because they saw that people were using the Chaos Emeralds for evil, and therefore equipped the gem to be able to negate the energy of the Chaos Emeralds should it be needed. It has been in existence for thousands of years (at least since the time the Knuckles Clan Echidnas were thriving) and has a large connection to the equally mysterious Chaos Emeralds, along with the being known as Chaos. In the present day, the Master Emerald is currently being guarded by Knuckles the Echidna.

Powers and Traits
The Master Emerald is regarded as the most powerful relic on Earth, possessing unbound and infinite power even more powerful than the Chaos Emeralds. As its primary function, the Master Emerald has the power to fully control everything that the Chaos Emeralds do, which grants it the ability to both negate and empower Chaos Emeralds, meaning it can stop the Chaos Energy of the Chaos Emeralds, or enhance them. The Master Emerald's energies can as well be harnessed to initiate a super transformation as seen in Mecha Sonic's case.

The Master Emerald has also been seen creating three-dimensional holographic images within itself (thus suggesting that the Master Emerald is in fact sentient). In addition, if the Master Emerald is broken into several pieces, it can repair itself if the shards are brought back together. However, the shattering of the emerald seems to give the shards an explosive trajectory, causing them to fly a great distance which makes the task of gathering them rather painstaking.

As revealed in Sonic Rivals, the Master Emerald is a transcendental object that exists simultaneously in all time lines across the time-space continuum. That means should the Master Emerald disappear in one time frame, it would cause a chain reaction that would make the Master Emerald disappear in all existing time frames.

Only Knuckles, Chaos and Tikal are able to talk to, command, and control the Master Emerald. On most occasions, for Knuckles and Tikal to connect to or unlock the power of the Master Emerald, they must recite an ancient quote: "The servers are the seven Chaos. Chaos is power, power enriched by the heart. The heart is the controller. The controller serves to unify the chaos."

Sonic & Knuckles
The Master Emerald could be seen early in Sonic & Knuckles being used to create Super Emeralds from Chaos Emeralds if the player accessed Special Stages. It would appear later being stolen from its altar by Dr. Ivo "Eggman" Robotnik to power his Death Egg, a doomsday weapon. It was retrieved by Sonic or Tails (depending on the player's choice) and was returned to Angel Island.

In Knuckles' playthrough, which occurs after Sonic or Tails' playthrough (due to the lack of a Death Egg and the fact that Sonic and Knuckles are now friends), the Master Emerald is again stolen, this time by one of Eggman's remaining Badniks, although it seems to have been part of a deal with the Sonic-shaped robot Mecha Sonic, that Sonic or Tails battled earlier. Mecha Sonic used the Master Emerald to significantly augment his powers, turning into a super-like state. "Super Mecha Sonic" was defeated by Knuckles anyway, as Mecha Sonic occasionally had to go back to the Emerald to recharge, since he couldn't absorb all the power into his being. As soon as Knuckles defeated Mecha Sonic, the area the two were on crumbled, but Sonic appeared in his biplane to save Knuckles and the Master Emerald, and it was again brought back to Angel Island. However, in an alternate ending should all Chaos Emeralds fail to be collected, Knuckles would lose the Master Emerald after the battle, as Angel Island descends into the sea.

Sonic Adventure
The Master Emerald appeared again in Sonic Adventure for the Sega Dreamcast, where it was again shown keeping Angel Island afloat. The Emerald also held within it the ancient monster known as Chaos along with the ancient controller of the Master Emerald and the Chaos Emeralds, and an Echidna female named Tikal. In the game, it was shattered by Dr. Robotnik to release Chaos, causing Angel Island to fall. In the duration of the game's storyarc, Knuckles collects the shattered pieces of the Master Emerald from a variety of locations, and ultimately repairs the Emerald.

Sonic Adventure also revealed that 4,000 years ago, the Knuckles Tribe Echidna had tried to steal the Master Emerald along with the Chaos Emeralds, both in an altar on the outskirts of the Tribe's city, in order to obtain ultimate power. To do this, they had to drive away the Chao that lived there. Chaos, who was their guardian, appeared and destroyed most of the Knuckles Tribe in a fit of rage, and in order to stop him, Tikal pleaded with the Master Emerald to calm him down. The Emerald then absorbed both Chaos and Tikal into itself, and continued to surge energy into a large part of the continent, making it float into the air with the remaining Echidnas, producing what is now Angel Island.

Sonic Adventure 2
The Master Emerald was again a source of contention as Knuckles fought with Rouge the Bat for possession of it in Sonic Adventure 2. Doctor Eggman tried to steal it again while they were distracted, but Knuckles purposely shattered the Emerald in order to keep it out of his hands. Knuckles and Rouge then set off separately to gather the shards of the Emerald for their own reasons. He managed to recover most of the Emerald shards, although after they briefly collided with an asteroid and opened up the cargo bay of a space shuttle, he was forced to ditch his friends (and nearly killed them by crashing the shuttle) in order to re-recover the lost emerald shards.

Once all the pieces had been collected the Emerald was reformed by Knuckles. When Space Colony ARK started to fall (due to an automatic system when all seven Chaos Emeralds were gathered in the central control room), Knuckles used the Master Emerald to try to stop the disaster in the Eclipse Cannon's Core, which resembled the Emerald Shrine on Angel Island, to negate the Chaos Emeralds' power.

Sonic Battle
When Sonic went to fight Emerl on the Death Egg in Sonic Battle, he brought the Master Emerald with him, hoping it would negate the Chaos Emeralds that powered Emerl. However, the Master Emerald was shattered by a crazed Emerl, as he was bothered by the light it produced. It was most likely put together again, as it appears in Sonic Advance 3, which is very likely situated after Sonic Battle.

When the Master Emerald appears, Sonic says "a Master Emerald!". This is most likely a translation error, especially because in the next sentence he refers to it as "the Master Emerald."

Sonic Heroes
The Master Emerald played no role in Sonic Heroes, but it was mentioned by Rouge the Bat in the last movie of Team Dark's Story. She says she "might as well go after that Master Emerald, since that irritating ECHIDNA is here!". Shadow responds, saying, "Some things never change, do they?", hinting that he managed to remember her rivalry with Knuckles. It is later hinted at in the ending of the final story, when Rouge the Bat mentions "stealing someone else's treasure," with Knuckles deducing after hearing the remark that she's going to steal the Master Emerald.

Sonic Advance 3
The Master Emerald then had a somewhat important role in Sonic Advance 3. After Eggman uses Chaos Control to split the world into seven parts, Sonic and Tails travel to the Master Emerald in order to use its Chaos Emerald-negating powers to undo the changes. After the heroes find it, the final boss is then fought at the Master Emerald altar. After the boss is defeated, the Master Emerald releases a bright light and repairs the world.

Sonic Rivals
In Sonic Rivals, Eggman Nega, masquerading as Eggman, stole the Master Emerald and used a special camera to turn it into a card, forcing Knuckles to find him and get it back. The game also stated that the Master Emerald exists in all moments in time simultaneously, so when Eggman Nega transformed the Emerald into a card in one moment in time, it disappeared from all other points in time. The Master Emerald is also one of the 150 collectible cards in the game.

Sonic Rivals 2
In Sonic Rivals 2, the Master Emerald was once again stolen. Working with Rouge, Knuckles uses an Emerald detector he found to help locate the Master Emerald without luck, as it's revealed at the end of the game the Master Emerald is in fact inside the detector. It is also in the card "Knuckles and the Master Emerald", but strangely, only Knuckles is shown on the card. This is because it is a cropped image from Sonic Adventure.

Sonic Chronicles: The Dark Brotherhood
In Sonic Chronicles: The Dark Brotherhood, Pir'Oth Ix uses the Master Emerald to create a gateway to the Twilight Cage and at the end of the game he uses either the Chaos Emeralds, the Master Emerald, or "the power of Nocturne itself" to achieve his Super State. Later, Knuckles takes the Emerald back.

Sonic Riders: Zero Gravity
Eggman mentions the Master Emerald in Sonic Riders: Zero Gravity when clearing Mission 4 of Astral Babylon with an Extreme Rank.

Sonic & Sega All-Stars Racing
In Sonic & Sega All-Stars Racing, Knuckles' All-Star Move uses the Master Emerald. It is revealed that Knuckles can use the Master Emerald to absorb power. In this increased power state, Knuckles is able to fly above the ground and charge up energy in his right fist. This huge build up of energy allows him to punch the ground so hard that everyone on the track will be hurt and bounced up in the air. In this state Knuckles also has increased speed, which can be used to get closer to first place.

Sonic & All-Stars Racing Transformed
In Sonic & All-Stars Racing: Transformed, the Master Emerald appears when Knuckles uses his All-Star Move. in this game, he can use the Master Emerald's power to use an energy attack similar to Shadow's Chaos Blast.

Size Dispute
The Master Emerald's size and shape seems to change over time; in games such as Sonic & Knuckles and Sonic Adventure, the Master Emerald is fairly larger than Knuckles, while in other games such as Sonic Adventure 2 and Sonic Chronicles: The Dark Brotherhood depicts it as being about the same size as a Chaos Emerald. Also in Sonic Rivals 2, it was small enough to fit inside Eggman's Emerald Detector.

While these appearances may seem to contradict themselves, it is actually a demonstration of the Master Emerald's ability to change its size according to its owner's will. This is firmly demonstrated by Knuckles in Sonic Adventure 2: After Knuckles restores the Master Emerald at the end of Sonic Adventure 2, he is able to shrink it down to the size of his hand. Then after Shadow defeats the Biolizard, Knuckles puts the Master Emerald into the core of the Space Colony ARK and he is able to enlarge it to a size slightly larger than himself.

Sonic the Comic
In Sonic the Comic, the Master Emerald is not an eighth emerald separate from the main group of seven, but is rather the green Chaos Emerald of the seven Chaos Emeralds at the peak of its power. While it is the most powerful emerald, it does not have any particular powers of control over the others, this role being filled by the Grey Emerald. As in other continuities, the Floating Island will fall out of the sky if it does not have the Master Emerald to power it, although this does not happen immediately: once when the Emerald was stolen, Knuckles was still able to pilot the Floating Island and activate an ancient weapon system, with which he destroyed the newly-rebuilt Death Egg.

The Master Emerald was first mentioned as a distinct entity when Doctor Robotnik sent Metallix to steal it so that he could use it to power his Death Egg. Sonic was able to recover the Emerald, which he then used as a bargaining chip to convince Knuckles to allow the Emerald Hill Folk to settle in the Mushroom Hill Zone.

The original Master Emerald was destroyed and its power absorbed by a robot under the command of Doctor Zachary; the robot's severed head acted as a substitute until Knuckles constructed a new Emerald and transferred the robot's absorbed Chaos Energy into it.

Archie Comics
In the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics, the Master Emerald was created after Miles "Tails" Prower used the Chaos Syphon to collect the energies of Mammoth Mogul and Enerjak's Chaos Emeralds, and merge them with the two that were keeping Angel Island afloat. As a result, the Master Emerald has the power of fourteen Chaos Emeralds. As with the Chaos Emeralds that kept the Island aloft before it, the Master Emerald is protected by Knuckles, and also by his relatives in the Brotherhood of Guardians.

As such a massive power source, it has been targeted by many villains, including Dr. Eggman. Currently, the Master Emerald is in the care of Knuckles' father Locke and the Dark Legion, following the repulsion of Eggman from Angel Island and the disappearance of the rest of the Brotherhood. The Master Emerald has been involved in several plots, and was used to give more power to Chaos and provided Evil Sonic with the energy to become Scourge the Hedgehog. It was also the only Emerald to be rescued from A.D.A.M.'s summons, an effort brought about by the efforts of both Locke and Dr. Finitevus.

Finitevus later secured stewardship of the gem, fooling Locke into handing the duties over to him by having the Destructix attack a group of Dingoes. His intention: to use the power of the Emerald to restore Dimitri-who had once been Enerjak, but lost his powers to Mammoth Mogul-to his former glory. However, Finitevus soon revealed that he had fooled Dimitri-as well as Dark Legion leaders Remington and Lien-Da into thinking that he would give them the Emerald's power, when in fact his intent was to use it to brainwash Knuckles into becoming a new Enerjak. His plan succeeded, and the new Enerjak went on a reign of terror before being confronted by Super Sonic, who was able to thwart the spell Finitevus had placed on the Emerald to avoid being affected as Knuckles had been. The resulting battle resulted in the separation of the Master Emerald's Shrine from the rest of Angel Island. Finitevus then revealed that his spell on the Master Emerald-and thus on Knuckles-could only be unlocked by the sacrifice of a person's life. Locke chose to lay down his own life to rescue his son, dying to undo Finitevus' spell. The Master Emerald has since been left in its new position on Shrine Island, which the Chaotix connected to the rest of Angel Island by building a bridge.

Following the events of Worlds Collide, the Master Emerald was once again situated on Shrine Island, but its origins and history matched that of the games universe. During the Shattered World Crisis, Chaos and Tikal emerged from the Emerald again in order to help the heroes of Mobius restore the planet to its proper condition. Charged with finding Light Gaia, Knuckles left Relic the Pika and Fixit, her Gizoid-like assistant, to guard the Master Emerald in his place. Subsequently, it would be targeted by the fiendish alien Eclipse the Darkling, prompting Shadow the Hedgehog to demand that it be relocated to a G.U.N. facility. This angered Knuckles, and the pair immediately began fighting over the issue.

Sonic X
The Master Emerald doesn't play an important role in the early part of Sonic X. However, after a giant Chaos Control brings the worlds of Sonic and Earth together, it appears on Earth along with Angel Island. During the Chaos Saga, it is then shattered by the release of Chaos, leading to Knuckles' search for the fragments across various areas. Later, it served to contain Chaos and Tikal, showing certain individuals visions of the past and is eventually put together.

Later during the Shadow Saga, the Master Emerald is stolen by Rouge the Bat (unlike the game, it is never shattered) and taken to Space Colony ARK. Knuckles follows and battles her, and wins the Emerald back. Later, Knuckles uses it to drain the Chaos Emeralds of power, shutting down the engines that propel the colony towards the planet.

In the second series/season 3, the Master Emerald first serves as the power source for Christopher Thorndyke's crossover into Sonic's world. As a result of the time difference between Earth and Sonic's world, the six years Chris has aged back in his world are stored inside the Master Emerald, returning him to his childish appearance, at least that was Eggman's theory. The Master Emerald also serves to power the Blue Typhoon space ship, which Sonic and co. use to travel around the galaxy and battle the Metarex. Its most important use is to power the Sonic Power Cannon, a massive cannon that is one of the few weapons effective against Metarex. The Master Emerald is left shattered and powerless after an attempt to use the Sonic Power Cannon to destroy the Metarex leader Dark Oak. Oak absorbs the energy and fuses with Chaos, while Chris' age data is corrupted, preventing him from returning home through that method.

Trivia

 * In Sonic the Hedgehog 2 Beta, there is a large green object shaped like an emerald in Hidden Palace Zone, which was often believed to be the Master Emerald. However, it was just a rock that Sonic could break to enter the tube that is below. (Or, in the 2013 re-release, a spring would be hidden in it).
 * The Master Emerald that appear in the Tikal visions in Sonic Adventure is much darker than the Master Emerald that appear elsewhere in the game.
 * According to a prototype plot line shown on Sonic HQ for the Archie Comics post issue #134, a second powerful jewel known as the Master Geode would later be introduced. This gem would have become a point of conflict for Mammoth Mogul, Dr. Eggman, the Iron Queen, and Rouge the Bat before being shattered. Knuckles would have gained omnipotence from exposure to the gem, and could absorb power from its fragments. However, given that most of the other plots in this article have been rendered impossible, it seems unlikely that the Master Geode will ever make an appearance.
 * In Sonic Adventure, after beating the game, the player can visit the Emerald Altar on Angel Island and see the incomplete Master Emerald with a small chunk missing (as a select few characters). However, in Knuckles' and Super Sonic's story, it is 100% complete.
 * The Master Emerald has been used to transform a character into a Super State at least twice in the game series. Once by Mecha Sonic in Sonic and Knuckles, and once by Ix in Sonic Chronicles: The Dark Brotherhood.
 * An accessory of the Master EmeraldAccEmeraldKnuckles.jpg was included with Knuckles late-2012 by Jazwares.
 * The Master Emerald is constantly being stolen, and was broken twice (Sonic Adventure, and once in Sonic Adventure 2 and thus Sonic X).
 * It was shown that Knuckles and maybe other guardians could change the size of the Master Emerald, as shown in Sonic Adventure 2 when it was about as big as Knuckles and Rouge at one point, and about the size of a Chaos Emerald in another. Or it was just a program mistake.
 * Since it has the same properties as the Chaos Emeralds, characters have been seen using its power to go Super at various points in the Archie comics. Even Ray jumped on top of the Master Emerald and pretended to use its power to go "Super Ray" to scare the Flying Dingoes.
 * If one were to perform a certain glitch with Tails in Sonic Adventure to get him through to the outside area of Angel Island, the Master Emerald would be completely gone from the altar.
 * It is possible that the Master Emerald, much like the Chaos Emeralds, is sentient. As Knuckles has been seen talking to the Master Emerald a few times and in Sonic Adventure, the Master Emerald showed Knuckles a holographic image of the Egg Carrier, where he found the remaining pieces of the Master Emerald.
 * The Master Emerald and the green Chaos Emerald, are the only two emeralds to be green like emeralds in real life.