The Master Emerald (マスターエメラルド Masutā Emerarudo?) is an object that appears in the Sonic the Hedgehog series. It is a massive green emerald and a mystical relic of great power that acts as a counter to the Chaos Emeralds, possessing the ability to nullify and control the Chaos Emeralds' energies. This makes it a very powerful and valuable gem.
The Master Emerald rests on Angel Island, usually in the Altar of Emerald, where its power keeps the island afloat in the sky; without it, the island will fall down. It also served as the prison for Chaos and Tikal, until the both of them were released in recent times. Over the last three millennia, the Master Emerald has been guarded by the surviving members of the Knuckles Clan in order to keep the tragedies that it has been involved in from ever repeating themselves. In the present day, its current guardian is Knuckles the Echidna, the last living descendant of the Knuckles Clan.
Though there has been several attempts to steal or destroy the Master Emerald over the course of recent history, Knuckles and various other heroes have always thwarted those plans and restored the Master Emerald to its resting place on Angel Island.
The Master Emerald is presented as a massive and green, brilliant cut jewel. While its size appears to be depicted inconsistently, this is merely a result of the Master Emerald's ability to change size according to its guardian's will; notably, during the second part of the Angel Island incident, it was shown to be slightly shorter than Dr. Eggman, while during the Chaos incident, it was roughly the height of individuals like Sonic and Knuckles. At one point during the Space Colony ARK incident, it could even assume a size small enough for it to fit in Knuckles' palm.
Powers and traits
Noted to possess massive energy readings akin to a giant Chaos Emerald, the Master Emerald is one of the most powerful relics on Sonic's world. In fact, the special abilities it commands alone makes it very powerful.
The Master Emerald's most famous and recognized ability is the power it holds over the seven Chaos Emeralds. Being able to control the Chaos Emeralds, the Master Emerald contains special powers that can neutralize the energy of said Emeralds, effectively nullifying the energies of the otherwise powerful gems and rendering them inert. Conversely, it can potentially amplify their powers as well. In addition, having been liken to a large Chaos Emerald, it radiates the same energies as the Chaos Emeralds. It fact, it has proven itself to house unbound and incredible amounts of chaos energy that rival those of the seven Chaos Emeralds, which together hold enough energy to bestow someone unlimited power and energy; notably, by harnessing the energies of the Master Emerald, Mecha Sonic was able to attain a short-lived Super State. These impressive energies can be harnessed directly from the Master Emerald for a variety of purposes. Its energies in particular are ideal for empowering beings or powering machinery and weapons as large and vast as the Death Egg.
In addition to the above, the Master Emerald possesses a variety of other powers. It can for example serve as a container for the purpose of sealing beings like mortals and deities inside of it, as in the case of Chaos and Tikal, although this process will strip a mortal being like Tikal of their corporal form, reducing them to a mere spirit. It can also display three-dimensional images within itself as a way communicating with others. Its powers can even be used to perform certain reality-warping feats, such as transporting an entire island through time and restoring a planet split into different pockets of reality with Chaos Control. Additionally, the Master Emerald has the ability to change its size at the behest of its guardian, as displayed by Knuckles during the Space Colony ARK incidence. The Master Emerald is as well a unique, transcendental object that exists simultaneously in every time frame across the time-space continuum. That means should the Master Emerald disappear from existence in one time frame, it would cause a chain reaction that would make it vanish from all existing time frames too.
Like the Chaos Emeralds, the Master Emerald seems to possess some sort of sentience and self-awareness. Notably, it once appeared on its own in an attempt to stop a rampaging Emerl and it has been known to silently communicate with Knuckles using its own image-displaying abilities.
While the Master Emerald can have its energies harnessed without restrictions, the only ones capable of fully controlling the Master Emerald and make use of its abilities are the members of the Knuckles Clan with strong ties to the gem, such as Tikal and Knuckles. To unlock its power and utilize its abilities, these individuals must on most occasions recite Tikal's Prayer.
Like the Chaos Emeralds, the Master Emerald is not indestructible, and can be shattered if enough force is applied to it. In addition, shattering the Master Emerald seems to give its shards an explosive trajectory, causing them to fly a great distance from their point of origin, which makes the task of gathering them rather painstaking without proper equipment or experience as a treasure hunter. However, if the Master Emerald is shattered, it can repair itself if its shards are brought back together. This process can be applied if all its shards are brought together, or just partially if only a fraction of its shards are regathered. Also, when putting itself back together, the Master Emerald gives off a flash of green light.
Where the Master Emerald comes from is not known, its origin shrouded in mystery. What is known is that it has coexisted alongside the Chaos Emeralds, powerful gems of which it is capable of neutralizing the energies of, for millennia. Furthermore, an ancient mantra came into existence at some point that would explain the Master Emerald's relation to the Chaos Emeralds, although its true meaning were eventually forgotten over the ages.
Approximately 3,000 years ago, the Master Emerald was located in the Altar of Emerald, residing in the center of this structure with the seven Chaos Emeralds situated on pillars around it, where they were revered as a sacred power. Back then, the Master Emerald's altar served as the home of a colony of Chao. The Master Emerald, along with its altar and its contents and inhabitants, were in turn guarded by Chaos, a Chao mutated into a god-like entity by the Master Emerald. The knowledge about the Master Emerald, however, dimly endured among the members of the ruling family of the Knuckles Clan in the form of its ancient mantra, which had been passed down from generation to generation. This mantra eventually ended up with Grandma, who in turn passed it onto her granddaughter, Tikal, who would ponder about its meaning. Meanwhile, Chaos would thwart all of the Knuckles Clan's attempts to steal the Emeralds from its altar. After Tikal met Chaos and gained its trust though, Tikal was allowed inside the Altar of Emerald. There, she found the Master Emerald in its center, and the sight of the gem made her piece together the true meaning of her clan's ancient mantra.
Tragedy eventually struck when Pachacamac, the leader of the Knuckles Clan, launched a violent attack on the Master Emerald's altar in order to seize the seven Chaos Emeralds and their power for his clan, setting the altar ablaze. During the attack, Pachacamac and his men injured Tikal and the altar's native Chao. The profound act of discrimination invoked the anger of Chaos, who used the Chaos Emeralds to transform into Perfect Chaos and annihilate Pachacamac and his men. However, Chaos, now a corrupt being, would not stop its rampage. In an effort to stop Chaos, Tikal turned to the Master Emerald, believing it could stop Chaos and the power it used before it could destroy the world. Reciting the ancient mantra, Tikal begged the Master Emerald to stop Chaos. In response, the Master Emerald emitted a bright light and sealed Chaos inside itself along with Tikal's consciousness, at the cost of Tikal's corporeal form.
In the aftermath, the survivors of the Knuckles Clan suspended the Altar of Emerald and its surrounding area into the sky using the Master Emerald's power, creating Angel Island. There, the Knuckles Clan took up residence and began bearing the duty of observing and protecting the sealed Master Emerald, so that an incident like that with Chaos could never happen again. Over the centuries, the Knuckles Clan seemingly upheld their vow and protected the Master Emerald. As time passed however, the few surviving members of Knuckles Clan became even fewer until only Knuckles the Echidna remained to guard the Master Emerald. Brought into the world to defend the Master Emerald, Knuckles assumed this role, knowing from innate knowledge that this was his purpose without being familiar with why or the history behind the Master Emerald, and so spent most of his life in solitude.
Sonic the Hedgehog 3 & Knuckles
Sonic the Hedgehog 3
In Sonic the Hedgehog 3 and the lock-on game, Sonic the Hedgehog 3 & Knuckles, after the Death Egg crash-landed on the Floating Island, Dr. Robotnik detected the energy of the Master Emerald that slipped out from the cracks in the island created by the Death Egg's impact. Discovering that the Master Emerald's power could be used to get the Death Egg flying again, the doctor began looking for it. Along the way, Robotnik met Knuckles, the guardian of the Floating Island and the Master Emerald itself, and tricked him into thinking that Sonic and Tails, both of whom were hot on the doctor's trail and would inevitably throw a wrench into his plans, were evil-doers coming to steal the Master Emerald. As such, Knuckles would repeatedly interfere with Sonic and Tails' mission to destroy the Death Egg in an effort to keep the Master Emerald safe.
Sonic & Knuckles
In Sonic & Knuckles and the lock-on game, Sonic the Hedgehog 3 & Knuckles, the Master Emerald had been put into the altar in Hidden Palace Zone. There, Sonic and Tails stumbled upon the entrance to the Master Emerald's hiding place where they found the massive gem. Riddled with questions upon seeing the Master Emerald, the two left it behind to get some answers. Not long after, Dr. Robotnik made his move by attempting to steal the Master Emerald from its altar in Hidden Palace Zone while Knuckles was busy fighting Sonic. As Robotnik used his Egg Mobile to haul the Master Emerald away though, Knuckles discovered the theft and tried getting the Master Emerald back, only for Robotnik to electrocute him with a feature from his Egg Mobile and escape with the Master Emerald. With the Master Emerald in hand, Robotnik was able to relaunch the Death Egg, but Sonic and Tails soon got onboard his space station to reclaim the Master Emerald. Using a giant mech powered by the Master Emerald's energy, Robotnik took up arms against Sonic onboard the Death Egg- However, his mech was still destroyed by Sonic, which triggered a chain reaction that made the entire Death Egg collapse. Hauling the Master Emerald away with him using the Egg Mobile, Robotnik ultimately made it to his Final Weapon and tried making his escape into space with the Master Emerald onboard. However, he found himself pursued by Super Sonic, who managed to cripple Robotnik's Final Weapon, leaving its unshielded mech to escape with the Master Emerald in its hands. However, that mech got destroy by Sonic too, leaving the Master Emerald to be snatched by Sonic, who flew down to earth with it, where Tails appeared in the Tornado in time to catch a de-powered Sonic and grab the Master Emerald with a tow cable. The two then brought the Master Emerald back the Floating Island, allowing the island to rise into the sky once again.
Unfortunately, the Master Emerald soon after got stolen again. As Knuckles chased an EggRobo all the way to Sky Sanctuary Zone, he found the Master Emerald in the clutches of Mecha Sonic. As Knuckles duked it out with Mecha Sonic, the robot would resort to harnessing the Master Emerald's power, allowing it to attain a Super State: Super Mecha Sonic. However, its Super State would not last long, thus forcing Mecha Sonic to constantly return to the Master Emerald to recharge itself and transform again. Exploiting this, Knuckles defeated Mecha Sonic, although his victory resulted in their area in Sky Sanctuary Zone to crumble to pieces, leaving the Master Emerald to fall down from the sky with Knuckles. Fortunately, Sonic swooped in in the Tornado and caught Knuckles on top of his biplane's wing with the Master Emerald in Knuckles' hands. The two subsequently returned the Master Emerald to the Floating Island, allowing the falling island to regain flight.
In Sonic Adventure, its enhanced port Sonic Adventure DX: Director's Cut, and the 2010 remaster, the Master Emerald was residing in the Altar of Emerald on Angel Island. During one faithful night however, while Knuckles was sleeping nearby the Master Emerald, Dr. Eggman arrived at Angel Island in his Egg Carrier and blew up the Master Emerald from a distance in order to free Chaos from its confinement inside the Emerald and use it to conquer the world. While the attempt was successful, the Master Emerald's shattering freed Tikal's spirit from the Emerald as well. Nevertheless, the explosion scattered the majority of the Master Emerald's shards all over the nearby areas, leaving only the Master Emerald's broken base in the altar. Furthermore, with the Master Emerald now gone and its power dispersed, Angel Island could no longer stay airborne, and so crashed down into the ocean on the coast of the Mystic Ruins.
Going on a hunt for the Master Emerald shards, Knuckles located its shards in Speed Highway, Casinopolis, Red Mountain and Lost World, and brought them back to the Altar of Emerald. There, Knuckles released the shards, which in turn gathered around the broken base of the Master Emerald and fused together, rebuilding the Master Emerald. However, Knuckles noticed that it remained incomplete, as it was still missing a few pieces. It was then that the Master Emerald showed Knuckles an image of the Egg Carrier inside it, which Knuckles took as a sign that the Master Emerald's remaining shards could be found onboard that airship. Making it onboard the Egg Carrier, Knuckles soon found the last shards of the Master Emerald, along with six of the Chaos Emeralds, and brought them back to the Altar of Emerald. There, the final shards fused with the Master Emerald, finally restoring the gem to its former glory and allowing Angel Island to rise into the air once more. In addition, Knuckles adorned the Master Emerald's altar with his six Chaos Emeralds.
Not long after, Angel Island fell from the sky once more, in spite of the Master Emerald remaining intact and on the island. As Knuckles suspected that this had something to do with the Chaos Emeralds however, Chaos appeared, took out Knuckles and stole the Chaos Emeralds. When Chaos later transformed into Perfect Chaos and began wrecking Station Square, Tikal appeared before Sonic and insisted that Chaos had to be sealed in the Master Emerald once more, or Chaos would destroy the rest of the world. However, knowing that just sealing Chaos in the Master Emerald would not quell the anger in Chaos' heart, Sonic ultimately resolved this by becoming Super Sonic and neutralizing Chaos' negative feelings with his power, allowing it to depart with Tikal in peace.
Sonic Adventure 2
In Sonic Adventure 2, its enhanced port Sonic Adventure 2: Battle, and the 2012 remaster, the Master Emerald was stolen from Angel Island once more, this time by Rouge the Bat, prompting Knuckles to head out and retrieve it. After Knuckles corned Rouge in a desert region, the two of them had a dispute over whom the Master Emerald belonged to. As Knuckles tried to explain the importance of the Master Emerald by elaborating on its ability to neutralize the Chaos Emeralds however, Dr. Eggman appeared in his Egg Mobile and stole the Master Emerald, having tracked its signal to this location, while Knuckles was busy talking. Refusing to let Eggman get away with the Master Emerald, Knuckles shattered the gem with a powerful punch, causing it to break into several shards that scattered across the world.
From there, Knuckles and Rouge began race to find the Master Emerald's last shards first. While Rouge managed to find some of its shards in Dry Lagoon, Knuckles obtained several other shards in Wild Canyon, Pumpkin Hill and Aquatic Mine. When Knuckles later accompanied Sonic and crew on a trip to the Space Colony ARK in a space shuttle however, a stray meteor opened op the shuttle's cargo door and scattered the Master Emerald shards Knuckles had collected into space. These shards ended up in Meteor Herd and Mad Space. Crashing the space shuttle into the ARK, Knuckles hurried out to regather the shards. Meanwhile, Rouge, having detected Sonic and his crew's incursion, went to gather the last pieces of the Master Emerald for herself. After Knuckles and Rouge found the missing Master Emerald pieces, the two began fighting each other over them. In the end though, Rouge grudgingly gave her Master Emerald shards to Knuckles after he saved her life. With all the shards now in hand, Knuckles was able to fully reform the Master Emerald and take it with him.
When the ARK was later sent on a collision course with earth due to a program created by Gerald Robotnik and initiated by the Chaos Emeralds, which would result in an impact that would destroy the planet, Rouge proposed a plan: if the Chaos Emeralds' energies were what propelled the ARK towards earth, Knuckles could use the Master Emerald to shut down the Chaos Emeralds' energies and thereby stop the ARK's descend. With Knuckles agreeing to do so, he and Sonic got the Master Emerald into replica of the Altar of Emerald in the Cannon's Core. Reciting then Tikal's Prayer, Knuckles used the Master Emerald to stop down the Chaos Emeralds. While the plan worked, the Finalhazard would keep the ARK on its collision course. Fortunately, Super Sonic and Super Shadow defeated the Finalhazard and returned the ARK to its stable orbit with Chaos Control.
In Sonic Heroes, Rouge set her sights on the Master Emerald, seeing as the gem was currently unguarded because Knuckles was elsewhere at the time. After they had then defeated Metal Sonic, Rouge intended to follow through with her plan by teasing Knuckles with a remark about going hunting "for someone else's treasure." Deducing that she meant the Master Emerald, Knuckles went after her.
In Sonic Battle, the Master Emerald appeared on its own when Emerl, a robot powered by the seven Chaos Emeralds, threatened to destroy the earth with the Final Egg Blaster from the Death Egg, with the Master Emerald landing in Sonic's possession. Realizing that they could use the Master Emerald to stop the Chaos Emeralds powering Emerl, Sonic took the Master Emerald to the Death Egg, However, before the Master Emerald could be used for its intended purpose, it was shattered by a crazed Emerl, as he was bothered by the light it produced.
Sonic Advance 3
In Sonic Advance 3, after Dr. Eggman used the Chaos Emeralds to invoke Chaos Control and split the world into seven pockets of reality, the Master Emerald and its altar ended up in Chaos Angel. Sonic and his allies subsequently began making their way to the Master Emerald in order to use its powers to induce Chaos Control and undo Eggman's changes. When Sonic and co. arrived at the Altar Emerald however, they were intercepted by Dr. Eggman and Gemerl in the Hyper Eggrobo. Regardless, Sonic and his allies managed to defeat the villains and drive them off. The Master Emerald then unleashed its power as Chaos Control in the form of a column of light that restored the world to normal. Following then the heroes' victory over Ultimate Gemerl, Sonic and his friends made their departure while Knuckles remained behind to guard the Master Emerald.
Sonic Rivals series
In Sonic Rivals, Eggman Nega would use a special camera in his time to turn the Master Emerald into a card. As such, due to the Master Emerald's nature as a temporal singularity, the Master Emerald immediately disappeared from all existing time frames. Notably, in the present, the Master Emerald vanished in front of Knuckles on Angel Island, prompting Knuckles to go on a search for it. Furthermore, with the Master Emerald's powers available to him in its card form, Eggman Nega used it to bring Onyx Island to the present day.
Eventually arriving on Onyx Island, Knuckles found Eggman Nega, who taunted Knuckles by flaunting the Master Emerald's card in from him when he asked for the Master Emerald's whereabouts. Afterwards, Knuckles pursued Eggman Nega across Onyx Island. When they got to Colosseum Highway Zone however, Eggman Nega used the Master Emerald's card to teleport Knuckles to Sky Park Zone. Eventually though, Eggman Nega lost it and planned to turn the whole world into a card. To do that, he mounted his camera on his Egg Destroyer spaceship and then planned to fuel it with the Master Emerald's card, among others, with his energy transfer device. Knuckles and his allies however, managed to stop Eggman Nega. In the aftermath, Knuckles recovered the restored Master Emerald and planned to sent Onyx Island back to its time with it.
Sonic Rivals 2
In Sonic Rivals 2, the Master Emerald disappeared once more, prompting Knuckles to go looking for it again. Eventually, it ended up inside the Emerald Detector belonging to Eggman Nega. That device soon after got claimed by Knuckles and Rouge, the former having allied himself with the latter in order to find the Master Emerald. Unaware that the Master Emerald was inside the Emerald Detector, the pair used the device to track Chaos Emeralds. In the meantime, Knuckles hoped that the Emerald Detector could lead him to the Master Emerald.
After helping foil Eggman Nega's master plan, Knuckles discovered the Master Emerald inside the Emerald Detector when the device got damaged. As Knuckles planned to take the Master Emerald back home however, Rouge stole the gem while he was distracted and left, leaving Knuckles to chase after Rouge.
Sonic Riders: Zero Gravity
Sonic Chronicles: The Dark Brotherhood
In Sonic Chronicles: The Dark Brotherhood, the Master Emerald would reside on Angel Island while Knuckles and Tails went to deal with the Marauders, later known as the Nocturnus Clan. Eventually however, the Marauders acquired all seven Chaos Emeralds and used them to draw Angel Island to Metropolis. With the island on their turf, the Nocturnus Clan traveled to the island in order to steal the Master Emerald, which they needed to permanently escape the Twilight Cage and conquer Sonic's world. Although Sonic and his allies got in their way, the leader of the Nocturnus Clan, Imperator Ix, managed to reach the Master Emerald's altar inside an old temple where he got the Master Emerald and teleported away with it.
With the Master Emerald brought to Nocturne, Ix was able to open a wormhole into Sonic's dimension, creating a passage between Sonic's world and the Twilight Cage. As Nocturne began moving towards the wormhole however, Sonic and his crew caught up with Ix. Following then a climatic battle with Ix, Knuckles got the Master Emerald back. Though Ix retorted by using the Emeralds' power in Nocturne to attain a Super State, Super Sonic managed to take him down. Afterwards, Sonic and his crew fled back to their dimension with the Master Emerald.
Sonic & All-Stars Racing series
Sonic & Sega All-Stars Racing
In Sonic & Sega All-Stars Racing, Knuckles' All-Star Move incorporates the Master Emerald. When triggering his All-Star Move, Knuckles summons the Master Emerald above him for a moment. During this time, the Master Emerald spins around while Knuckles draws power from it. After that, the Master Emerald disappears while Knuckles is left able to glide down the track at high speed and throw chargeable punches into the ground so hard that they topple nearby racers.
Sonic & All-Stars Racing Transformed
In Sonic & All-Stars Racing Transformed, the Master Emerald appears when Knuckles uses his All-Star Move. When activating Knuckles' All-Star Move in this game, Knuckles transforms his Land Breaker into its plane form and summons the Master Emerald above him, where he keeps it suspended for the duration of his All-Star Move while it spins around. During this time, Knuckles can unleash green shockwaves using the Master Emerald's power to attack nearby racers.
In Sonic Runners, the Master Emerald was hidden away by Knuckles in a temple surrounded by lava. However, it was later discovered by Dr. Eggman, who went on a hunt for it. Once he caught news of this, Knuckles hunted Eggman down. However, by the time he got to the temple, Eggman had already stolen the Master Emerald. Eventually, Team Sonic caught up to Eggman and the Master Emerald. However, as Eggman tried making his escape with the Master Emerald upon his defeat at Team Sonic's hands, Knuckles smashed the gem into many Master Emerald Fragments to prevent the theft, its pieces scattering all over the place like green shooting stars. Afterwards, Team Sonic began tracking the Master Emerald fragment down.
Following a lead on a Master Emerald Fragment, Team Sonic eventually tracked it down, only for Metal Sonic to get to it first. Making his escape with the fragment, Metal Sonic brought it to Eggman. However, Team Sonic got it back after they followed Metal Sonic to Eggman and made him drop it. After later coming into possession of an Emerald Detector, Team Sonic began tracking the Master Emerald Fragments more efficiently, until they only had two fragments left to find. Their search for one of these fragments took them into the clouds. There, Knuckles found a Master Emerald Fragment that he and his team defended when Eggman showed up to claim it. After defeating Eggman, Team Sonic tracked the last fragment to a Pocky, who had come upon the Master Emerald Fragment and planned to give it to his mother for her birthday. As Team Sonic later tried trading the Master Emerald Fragment for a pearl necklace however, Eggman showed up and took both Pocky and the fragment. Eventually discarding Pocky, Eggman tried to escape with the Master Emerald fragment, but Team Sonic managed to catch up to him and make him surrender the fragment. Having now found all the Master Emerald fragment, Team Sonic went to the hidden temple to assemble the Master Emerald there. After they managed to clear Eggman out of the temple, Team Sonic pieced the Master Emerald's fragments together and restored the Master Emerald to its former glory. However, there was still the problem of guarding the Master Emerald from Eggman while Knuckles was away. Fortunately, the local Animals and Omochao offered their help. After assembling a small group of Animals to help them, the Animals would prove their usefulness by driving off Eggman when he tried stealing the Master Emerald again. Now assured that the Master Emerald was in safe hands, Team Sonic resume their adventure.
In Sonic Forces, months before the War to Take Back the Planet, Knuckles was resting next to the Master Emerald at the Altar of Emerald when he got interrupted by the arrival of Silver. Immediately after, a physical illusion of Pachacamac's village appeared on Angel Island, followed by the appearance of a Chaos Phantom Copy on top of the Master Emerald. Just as Knuckles and Silver defeated the Chaos Phantom Copy however, it and the village disappeared. Knuckles and Silver then left Angel Island to prepare for the trouble Silver was trying to warn Knuckles about, leaving the Master Emerald unattended. Despite this, Dr. Eggman did not find it necessary to steal the Master Emerald, having deemed its power inferior to his Phantom Ruby's.
Sonic Speed Simulator
In Sonic Speed Simulator, the Master Emerald makes an appearance during the "Treasure Hunt Event". Accordingly, the Master Emerald was originally in Knuckles' possession, but by freeing Amy from her crystal prison during "Save Amy Event", it created a blast that shattered the Master Emerald and scattered its Master Emerald Shards all over the worlds. As such, during the "Treasure Hunt Event", Treasure Hunter Knuckles enlisted the player to track down 3,000 Master Emerald Shards in order to reassemble the Master Emerald. Also, once the tasks of this event have been fulfilled, the Master Emerald can he found in the treasure pile next at Treasure Hunter Knuckles' camp in Green Hill.
In other media
In the Sonic X anime series, the Master Emerald is a powerful jewel originating from a parallel earth. Much like in the games, it is guarded by Knuckles the Echidna and it holds the power to control the Chaos Emeralds.
When Knuckles was transported to Earth, he spent most of his time looking for a way back home to continue protecting the Master Emerald. Ironically, the Master Emerald came to him when it was transported to earth during a giant Chaos Control. There, it came under Knuckles' protection again. Eventually though, the Master Emerald and everything from its world were returned home when their presence threatened to freeze time.
Six months later, the Master Emerald was used to power the Blue Typhoon, which Sonic and co. used to travel around the galaxy and battle the Metarex. In the final battle with Dark Oak, the Metarex's leader, Knuckles was forced to sacrifice the Master Emerald, leaving it shattered and powerless for the time being.
Books and comics
Sonic the Comic
In the Sonic the Comic comic series and its spin-offs published by Fleetway Editions, the Master Emerald is not an eighth emerald separate from the main group of seven, but is rather the green Chaos Emerald at the peak of its power. While it is the most powerful of them all, it does not have the powers to control 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, but rather over a course of hours.
Originally created by the Drakons, the Master Emerald was claimed by the Echidnas. During the next millennia, the Master Emerald and five of the Chaos Emeralds got split in two. On Mobius, they were targeted by Dr. Robotnik while Sonic and the Freedom Fighters kept them safe. In one of Robotnik's failed attempts to seize the Emeralds, the Master Emerald and the other Chaos Emeralds were rejoined with their missing halves and left on the Floating Island to be guarded by Knuckles. While multiple factions came to the island seeking the Emeralds, Dr. Zachary's attempt shattered the Master Emerald and Knuckles had to contain its energies in a broken robot until he found a new emerald for them.
In the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics, the Master Emerald was created after Tails used the Chaos Syphon to collect the energies of Master Mogul's twelve 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 was protected by the Brotherhood of Guardians.
After its creation, the Master Emerald would be targeted by several villains, such as Dr. Eggman, Scourge the Hedgehog and Dr. Finitevus, all while the number of its guardians dwindled. It was also the only Emerald to be rescued from A.D.A.M.'s summons during the Great Harmony. When Dr. Finitevus used the Master Emerald to turn Knuckles the Echidna into the fourth Enerjak, Sonic use it to become Super Sonic to hold off Enerjak long enough for Locke to use the Master Emerald to restore Knuckles, though at the cost of his own life. After that, Knuckles remained as the only guardian of the Master Emerald left.
Following the Super Genesis Wave, the Master Emerald's origins and history came to match that of its game counterpart. During the Shattered World Crisis, Knuckles the Echidna was forced to shatter it to keep it from being taken, and spent the remainder of the crisis reassembling it.
In the Sonic the Hedgehog comic series and its spin-offs published by IDW Publishing, the Master Emerald is a mystical emerald of great power that keeps Angel Island afloat in the skies. In this media, its past is virtually identical to its game counterpart's, up until after the events of Sonic Forces. Prior to the comic's storyline, Knuckles had to leave his post as guardian of the Master Emerald in order to fight in the Eggman War. After the war, Neo Metal Sonic conquered Angel Island during Knuckles' absence and took control of the Master Emerald, which he used to transform into Super Neo Metal Sonic, and then Master Overlord. Ultimately, however, Knuckles managed to retrieve the Master Emerald and return it to Angel Island.
In the Sonic the Hedgehog film series produced by Paramount Pictures and its spin-offs, the Master Emerald is a source of ultimate power with the ability to turn thoughts into reality. The most powerful weapon in the universe, the Master Emerald was created ages ago by the echidnas by merging the seven Chaos Emeralds together into a singular gem. The echidnas would subsequently use the Master Emerald at their own accord to defeat entire armies. Believing no one should possess such power, the owls stole the Master Emerald and hid it away on Earth, sparking a centuries-long feud with the echidnas.
The Master Emerald would be sought after by Knuckles, believing it to be his ancestral birthright. In the process, he teamed up with Dr. Robotnik. However, when they found the Master Emerald, Robotnik betrayed Knuckles by seizing the Master Emerald for himself and using it for his plans of conquering the multiverse. Though Sonic, Tails and Knuckles got the Master Emerald away from Robotnik, it got shattered and lost the Chaos Emeralds. Nevertheless, Knuckles managed to repair it, and he, Sonic and Tails formed a new order to safeguard it.
- In the Nick Arcade and Simon Wai prototype versions of Sonic the Hedgehog 2, there is a large green 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.
- The Master Emerald that appears in Tikal's visions in Sonic Adventure moves up and down and is much darker than the Master Emerald that appears elsewhere in the game.
- 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.
- If the player performs a glitch with Tails in Sonic Adventure to get him through to the outside area of Angel Island, the Master Emerald completely disappears from the altar.
- Since its debut, the Master Emerald has not been featured in any game where Knuckles does not also appear.
- Sonic the Hedgehog 3 (Sega Mega Drive) Japanese instruction booklet, pgs. 34-36.
- Sonic Team (23 June 2001). Sonic Adventure 2. Dreamcast. Sega. Area/Level: Wild Canyon. "Knuckles: The Master Emerald contains special powers that neutralize the energy of the Chaos Emeralds. That makes it very powerful!"
- Sonic Channel (Japanese). Characters: Knuckles. Sega. Archived from the original on 26 May 2019. Retrieved on 3 July 2015.
- Sega, SEGA HARDlight (19 September 2019). Sonic Racing. IOS. Sega. Area/Level: Knuckles the Echidna: Driver info. "Last descendant of the Knuckles Clan and protector of the Master Emerald."
- Sonic Team (23 June 2001). Sonic Adventure 2. Dreamcast. Sega. Cutscene: Cutscene 7 (Last Story).
- Sonic Team (9 September 1999). Sonic Adventure. Dreamcast. Sega. Area/Level: Mystic Ruins (Big's story). "Tikal: So these are the 7 Emeralds... ?! Could it be? The servers are... the 7 Chaos Emeralds... Unified by one that is the controller... The 7 Chaos... The controller itself... Could this be the Emerald that controls the 7 Chaos?"
- TailsTube #1 (feat. Sonic). YouTube. Sonic the Hedgehog (24 March 2022). Retrieved on 24 March 2022.
- Sonic Team (27 February 2004). Sonic Battle. Game Boy Advance. Sega. Area/Level: Emerald Beach (Shadow's Episode). "Sonic: I've heard that he who collects 7 "Chaos Emeralds" will be granted unlimited energy."
- Sonic Team (9 September 1999). Sonic Adventure. Dreamcast. Sega. Area/Level: Mystic Ruins (Knuckles' version). Cutscene: Cutscene 11.
- Backbone Entertainment, Sega Studio USA (7 December 2007). Sonic Rivals. Sega. Area/Level: Meteor Base Zone. "Knuckles: All right! I finally got the Master Emerald back! I'll use it to send Onyx Island back where it belongs in the future. While I'm at it, I might as well locate all the other treasures that Eggman turned into cards. This is going to be fun!"
- Sonic Advance 3 (Game Boy Advance) United States instruction booklet, pg. 4.
- Sonic Team, Dimps (7 June 2004). Sonic Advance 3. Game Boy Advance. Sega. Area/Level: Bad ending sequence.
- Backbone Entertainment, Sega Studio USA (24 November 2006). Sonic Rivals. Sega. Area/Level: Death Yard Zone. "Eggman Nega: Fine! If you want to know so badly, I'll tell you! I turned the Master Emerald into a card using my camera by taking a picture of it from the future Angel Island. Since the Master Emerald is a unique object that exists across the time-space continuum... When the future emerald was turned into a card, its existence in all the time frames vanished as well. / Knuckles: So that's why the Master Emerald disappeared from right in front of me! / Eggman Nega: So you finally understand. Using the power of the Emerald, I brought all of Angel Island here, into this time frame."
- Sonic Team, Sonic Team USA (27 February 2004). Sonic Battle. Game Boy Advance. Sega. Area/Level: Death Egg (Emerl's Episode).
- Sonic Team (9 September 1999). Sonic Adventure. Dreamcast. Sega. Area/Level: Mystic Ruins (Super Sonic's story). "Tikal: The 7 Emeralds are the servers. Chaos is power, enriched by the heart. The controller serves to unify the chaos. Uhh... The 7 Emeralds can change our thoughts into power. If this Emerald controls that power... Please, you must stop him!"
- Sonic Team USA (23 June 2001). Sonic Adventure 2. Dreamcast. Sega. Cutscene: Cutscene 7 (Last Story). "Knuckles: The servers are the seven Chaos. Chaos is power, power is enriched by the heart. The controller is the one that unifies the Chaos. Only you can do this; stop the Chaos Emeralds!"
- Sonic Team USA (19 June 2001). Sonic Adventure 2. Sega. Area/Level: Wild Canyon. "Knuckles: I did that to prevent the Master Emerald from being stolen, you idiot! If it's in pieces, I can restore it."
- Sonic Team (9 September 1999). Sonic Adventure. Dreamcast. Sega. Area/Level: Mystic Ruins (Tails' story). "Tikal: The servers are the 7 Chaos Emeralds. Hello there, friend. How are you? / ... / Tikal: Huh? It's something my grandmother taught me. I never to forget it. It goes like this... "The servers are the 7 Chaos. Chaos is power... Power enriched by the heart. The controller is the one that unifies the Chaos." But I'm still not sure what it all means. But the number 7...is the same as the number of Emeralds there are."
- Sonic Team (9 September 1999). Sonic Adventure. Dreamcast. Sega. Area/Level: Mystic Ruins. "Knuckles Clan tribesman': Chao? Sacred power? No way! I don't buy it. We're goin' in to get those special stones."
- BradyGames (1 November 2011). Sonic Generations Official Strategy Guide. BradyGames. ISBN 978-0744013429. "In Sonic Adventure the being known Chaos was originally a Chao, like Omochao. An encounter with the Master Emerald cause it to mutate into a liquid creature with godlike abilities."
- Sonic Team (9 September 1999). Sonic Adventure. Dreamcast. Sega. Area/Level: Mystic Ruins (Amy's story). "Knuckles Clan tribesman: We made a lotta money with our power. But whenever we tried to get the Emeralds, some strange force always stopped us."
- Sega of America. Knuckles the Echidna. Sonic Characters. Sega. Archived from the original on 5 March 2005. Retrieved on 26 October 2017. "Knuckles was born alone on Angel Island, brought into this world to defend the Master Emerald. That is Knuckles' destiny and fate. If Sonic exemplifies the wind, then Knuckles is the mountain: stern and unmovable. Knuckles is quick to anger, but cool and determined in battle. Even though he considers Sonic his friend, the disposition of the Master Emerald is his ultimate concern. His determination to protect the gem from harm or ill use is set in stone and is unshakable. He is often envious of the adventurous lifestyle Sonic lives and the fame that has followed from Sonic's deeds, but Knuckles is well known in his own right, as a treasure hunter versed in the martial arts."
- Sonic Team (9 September 1999). Sonic Adventure. Dreamcast. Sega. Area/Level: Opening sequence (Knuckles' story). "Knuckles: As far back as I can remember, I've been living here, on this dark island... Always guarding the Master Emerald from anything that can harm it. I don't know why I was given this job... Why it was my fate... Destined to be here...forever!"
- Sonic the Hedgehog 4 :: Episode I. Sega. Archived from the original on 30 May 2013. Retrieved on 26 January 2015.
- Sonic & Knuckles (Sega Mega Drive) Japanese instruction booklet, pgs. 12-13.
- Sonic Team USA (23 June 2001). Sonic Adventure 2. Dreamcast. Sega. Area/Level: Wild Canyon. "Knuckles: I'm Knuckles the Echidna. But you can call me Knuckles. Once again, the Master Emerald was stolen from Angel Island. The thief turns out to be this know-it-all bat girl of all things."
- BioWare (30 September 2008). Sonic Chronicles: The Dark Brotherhood. Nintendo DS. Sega. Area/Level: Metropolis Ground Zero. "Shade: Your military had set up around the base of the island. To conquer Angel Island, Ix needed to bring it to him. He used the Chaos Emeralds to draw the island over Metropolis, where we had set up our base. The plan was to assault the island on our turf, rather than attacking it with legions of soldiers underneath."
- BioWare (30 September 2008). Sonic Chronicles: The Dark Brotherhood. Nintendo DS. Sega. Area/Level: Metropolis Ground Zero. "Shade: To truly cross into this world, Ix needed to open the wormhole. And to do that, he needed the Master Emerald."
- Sonic Forces: Stress Test, "Stress Test"
- Gamefam Studios (16 April 2022). Sonic Speed Simulator. PC. Area/Level: Green Hill. "Knuckles: Hm, when we freed Amy from that mystical pink crystal, it created a blast that scattered all of my treasure across every zone."