Arakko is a sister entity of Krakoa. Both were once part of Okkara, a sentient island that existed in the South Pacific. Okkara became home to a nation of mutants, ruled by Apocalypse and his former wife called Genesis. Several thousand years prior to the Modern Age, Okkara was attacked by an enemy wielding a twilight sword and was split into two creatures, Krakoa and Arakko. In order to save Earth from being overwhelmed by the daemons unleashed by the sword, Genesis, her and Apocalypse's children, and the Okkaran society of mutants were sealed away together with Arakko to buy the world time. Apocalypse remained behind to prepare mutantkind for the daemons' inevitable return.
Later, the Mutants terraformed Mars and re-located Arakko and its inhabitants there and claimed the red planet as the capital of the Solar System and the first mutant world. The Great Ring consented to the plan and lent their aid. After the planet was made hospitable for life during a global event called the Hellfire Gala, Exodus, with the aid of Jean Grey and Lactuca the Knower, uprooted the island and sent it to Mars.
The nation of Arakko is a continuation of the mutant society of Okkara. Arakko proper was a walled city, protected from the encroaching Amenthi hordes by ten towers. While in Amenth, Arakko appears to have bordered a body of water, where Arakki pirates roamed.
Arakko is governed by the Great Ring, a council of omega-level mutants. The Great Ring has governed the nation for thousands of years, with the exception of a time Isca the Unbeaten referred to as "the fallow years".
Like its sister-nation of Krakoa, Arakko is governed by three principal laws:
Make more mutants
Destroy our enemies
Defend this broken land
Hardened by their constant battle for survival, the Arakki are a warlike people. They frown on weakness and eschew comfort, welcoming any challenge as a means of strengthening themselves. To suggest an Arakki requires the help of another is an insult. In addition" Arakko has twenty times more mutants than on Krakoa.
Mars