Overlander

Overlanders are slightly mutated, de-evolved descendants of humans on Mobius. They were a bi-product of the Xorda's Gene Bombs, which lead to the mutation of the planet's inhabitants. Unlike humans, Overlanders have four-fingers instead of five. They tend to be aggressive in nature and have strong feelings of xenophobia towards their Mobian counterparts.

Xorda Attack
Prior to becoming Mobius, the planet Earth's dominant species was the homosapiens (aka humans). During Earth's 21st century, the scientist Ivan Kintobor provoked the alien species known as the Xorda by capturing their emissary and dissecting it. As a result, the Xorda bombarded the planet with Gene Bombs, which were supposed to wipe out the human race and maintain the rest of the planet's environment as it was at the time. However, the Gene Bombs instead de-evolved the human population, creating Overlanders. (StH: #125, #148)

Early History and Development
Some time after the Xorda attack, the Overlanders were still a barbaric species. The Mobian Alexander attempted to integrate them into his all-species society of Mobotropolis, but their aggressive tendencies made their integration too dangerous. (StH: #71)

Unlike their Mobian counterparts, who wished to preserve the environment and therefore remained locked in the medieval age for centuries, the Overlanders hit the industrial age and later the atomic age, developing their capital city of New Megaopolis in the North-western hemisphere. (StH: #65)

War with the Mobians
Within the last century, the Overlanders and Mobians fought the Great War which lasted numerous years. While the Overlanders were initially defeating their medieval Mobian foes with relative ease, the tides turned when the Overlander scientist Julian Kintobor joined the Mobians and provided them with tactical information, battle strategies and technology. This ultimately resulted in the Overlanders' defeat. (StH: #50, #73, #74, #76)

Trek Through the Stars
Filled with shame and guilt over their unexplainable loss, the Overlanders, lead by Julian's brother Colin Kintobor, created two space ships and fled the planet in search of their own. After nearly 20 years of searching, they were unable to locate a hospitable world, and were forced to return to Mobius. (StH: #94)

Betrayal and Move
Upon returning to Mobius, the Overlanders found themselves welcomed to the city of Robotropolis by Dr. Eggman - an alternative dimension's version of the now-dead Julian Kintobor (aka Dr. Robotnik). Unbeknownst to them, Robotropolis was filled with deadly radioactive poisoning, which Eggman was immune to due to his robotic body. Eggman planned to keep the Overlanders ignorant of this until they were forced to undergo roboticization in order to become cured. However, the citizens of Knothole became aware of the deadly radiation, and warned the Overlanders, which decided to leave the city before it was too late. (StH: #93, #100, #105)

Shortly after this, the Mobians relocated the surviving Overlanders to the human city of Station Square, as the physical and cultural differences would make it impossible to share Knothole with them. Since then, the Overlanders were cured of their radiation poisoning and together with the human population of the city have formed the Republic of Station Square. (StH: #106, #107, #110)