Sonic's World

Sonic's World (ソニックの世界, Sonikku no Sekai) is the main setting of the Super Smash Bros.' Sonic series created by Yoshiharu Gotanda. It is the home planet of mobians and humans alike. Much of the world is governed by the United Federation which is led by the President.

Other territories are under the control of the Eggman Empire. However, even territories that are not completely under the Eggman Empire have bases stationed within them which are run by Egg Bosses.

During a skirmish with Dr. Eggman in recent times and over the subsequent period, Sonic, his allies, and several elements from Sonic's World got transported from their world to Earth. Eventually though everyone and everything from Sonic's world were returned to their home planet.

"Come on! Let's go home! To the planet as cool and blue as me!"
 * —Sonic, to Amy.

Areas

 * Chemical Plant
 * Green Hill
 * G.U.N. Fortress
 * Holy Summit
 * Metropolis
 * Mystic Jungle
 * Mystic Ruins
 * Never Lake
 * North Cave

Cities and territories

 * City
 * Eggman Empire
 * Avalon
 * Bullet Station
 * Metropolis
 * Emerald Town
 * Eggmanland
 * Meropis
 * Monopole
 * Soleanna
 * United Federation
 * Adabat
 * Apotos
 * Central City
 * Chun-Nan
 * Empire City
 * Holoska
 * Mazuri
 * Shamar
 * Spagonia
 * Station Square
 * Westopolis

Continents

 * Artika
 * Efrika
 * Eurish
 * Midesta
 * Northamer
 * Soumerca
 * Tralius
 * Yurashia

Islands

 * Angel Island
 * Shrine Isle
 * Babylon Garden (formerly)
 * Christmas Island
 * Cocoa Island
 * Eastwatch Islands
 * Eggman Island
 * Flicky Island
 * Newtrogic High Zone
 * Prison Island
 * Seaside Island
 * South Island
 * West Side Island

Main political factions

 * Eggman Empire
 * Egg Army
 * United Federation
 * Kingdom of Soleanna

Natural satellites

 * Little Planet
 * Lost Hex
 * Moon

Oceans

 * Northern Oceans
 * Great Blue Realm
 * South Ocean
 * Southern Oceans

Past
Sonic's world came into existence in the beginning of time. In that era, Dark Gaia and Light Gaia came to reside on it. Following a constant cycle, Dark Gaia awakens once every couple of millions of years to destroy the earth and Light Gaia then restores it in an event known as the time of awakening. The two of them would then return to sleep in the earth's core until they can awaken to continue the cycle.

Over 4,000 years ago, there were two warring civilizations of Echidnas known as the Knuckles Clan and Nocturnus Clan. In order to overcome their foes, Pachacamac, the leader of the Knuckles Clan, attempted to steal the mighty seven Emeralds from the Chao. His civilization along with the entire world was almost completely wiped out by their guardian Chaos in the process after he transformed into a terrible monster. Afterwards, the large jewel was known as the Master Emerald, and the other smaller ones were called Chaos Emeralds.

In that same time, a series of sentient weapons, the Gizoids, were created by the Nocturnus Clan, one of which was thought to have destroyed the "Fourth Great Civilization." In actuality, this Great Civilization was the tribe themselves, and they were all really pulled into a different dimension known as the Twilight Cage after conquering nearly all of the ancient world.

The alien Black Doom of the Black Arms seems to have been observing the planet for eons, as he has warped Glyphic Canyon to it over 2,000 years ago. His people's home, the Black Comet, passed by the earth every fifty years. However, it was eventually destroyed by the Eclipse Cannon when they posed a threat to the citizens of the world.

Fifty years before the present, aboard the Space Colony ARK, Professor Gerald Robotnik was forced by the President of that time to create the Ultimate Life Form. Aided by Black Doom, they created Shadow the Hedgehog. Gerald also studied the Gizoid, Chaos, and at least one Chaos Emerald. Later, GUN invaded the ARK and either imprisoned or killed all those related with "Project Shadow". This was because of their fear of Professor Gerald Robotnik's work. Gerald's granddaughter Maria Robotnik, who had become very close to Shadow, was killed and Shadow was sent to the surface. Gerald was later found and imprisoned on Prison Island under the pretense of disappearance, and heavily implied to have been executed by firing.

Sonic
The planet has recently been constantly pained by the professor's grandson, Dr. Ivo Robotnik, who also goes by the alias Dr. Eggman with number of his attacks and bases being taken place in different types of islands and earth's natural satellite. It was also attacked by the monster Chaos, threatened with impact by the falling ARK, invaded by the Black Arms, nearly sucked into a giant black hole (twice), broken apart and plagued by the hyper energy organism Dark Gaia, and had its very existence in space-time threatened on multiple occasions. All disasters have been stopped by Sonic and his allies who use the powers of the Chaos Emeralds to protect the world time and again. At one point, Eggman managed to take over 99% of the world after Sonic was defeated by his new henchman, Infinite. However, Sonic was soon rescued and with the combined efforts of the Resistance, Eggman was defeated and the world was freed.

Parallel timelines and the future
More than 200 years after Sonic's time, the people of the world had evolved to the point where they gained psychokinetic powers, which they would use in everyday life. During the centuries leading up to that point, the earth would be largely destroyed by Iblis. Amidst Iblis' dark reign, a resident of the future named Silver tried to stop Iblis for good under Mephiles the Dark's machinations by traveling back to Sonic's time to find the Iblis Trigger, the person responsible for releasing Iblis. When Solaris returned as a result of that, the deity sought to destroy all existing timelines, but was defeated by Sonic, Shadow and Silver. Solaris was then erased from history by Sonic and Princess Elise of Soleanna to prevent his wrath from being released, thereby changing the future for the better.