The Mysterious Cat Country, also called the Pais Misterioso, is a region of Mobius' southern continent located near Station Square and the Mystic Ruins. It is home to the settlement of the Felidae ruled by Queen Hathor, and serves as a border between the ruins and the ancestral lands of the Wolf Pack Nation.
Hundreds of years ago, the Mysterious Cat Country became the battle ground between the Felidae and the Echidnas, who had immigrated from Albion in search of a new home. The warrior caste of the immigrant Echidnas known as the Knuckles Clan came into conflict with the Felidae and remained to fight for their new land while the scientific elite left and found a new home in the continent of Downunda. The Knuckles Clan, seeking an advantage against their enemies, sought to use the local Chaos Emeralds, but in doing so angered the water creature Chaos, who then destroyed the clan. Despite having been wiped out, these echidnas forever colored the Felidae's attitude towards outsiders.
When Dr. Eggman attempted to reawaken Chaos for his own purposes, it caused a series of events within the Country and the surrounding regions. With the Master Emerald shattered, Angel Island crashed off the coast of the country. Fearing invasion, Queen Hathor accompanied some of her warriors to the fallen island and captured the Chaotix, thinking to use them as leverage against any would-be attackers. However, the Guardian Locke soon arrived, demanding the prisoners be released lest he finish the battle started by the Knuckles Clan so long ago. Hathor arranged for a duel between Locke and the Felidae champion Razorklaw, in order to determine whether or not the Chaotix would be freed. Once Razorklaw lost, Locke was eventually able to convince Hathor that those from the island had no intention of invading the Mysterious Cat Country, which Hathor eventually accepted. She showed the Guardian that ruins from the Knuckles Clan settlement still stood in the area, including a statue of Pachacamac standing atop a fallen Felidae warrior. Razorklaw was subsequently banished from the Felidae, and later joined the Eggman Empire with other exiles.
Eventually, the Mysterious Cat Country found itself with new neighbors: the Wolf Pack Nation. The wolves, traditional enemies to the Felidae, had decided to resettle in their ancestral homeland to the north of the Pais Misterioso. Both countries claimed rightful ownership of a relic known as the Ancient Onyx; however, it had recently gone missing, causing tempers to flare on both sides. Finding that each group claimed to not have it, Sonic the Hedgehog, accompanied by the heathen Felidae Big the Cat, went to the Mysterious Cat Country to discuss the matter with Queen Hathor. As an outsider, Sonic was met with great distrust, but eventually got the Queen to agree to allow him to search for the Ancient Onyx in order to work out an agreement with the wolves. However, Lupe and her pack soon arrived in the Country, bearing arms and demanding the Felidae return the Onyx, as Lupe believed they were lying. Meanwhile, Princess Sally Acorn discovered that the artifact had been stolen by a chapter of the Dark Egg Legion, composed of Razorklaw and his fellow exiles combined with traitorous Wolves under Drago Wolf. She was captured by the group, but fortunately Sonic was able to deduce what had happened. Convincing the Felidae and their Wolf neighbors to take part in an uneasy truce, he led them to the Mystic Ruins, where they found-and attacked-the Dark Egg Legion. After driving their mutual enemies out, the two sides agreed to terms for the Ancient Onyx worked out by Sally, in which the artifact would remain in the ruins in Felidae territory, to be retrieved by the Wolves when needed.
The Wolf Pack Nation