Cetra

The Cetra (セトラ, Setora), also known as "the Ancients" (古代種, Kodai-shu), are mentioned frequently in Final Fantasy VII, although few Ancients are actually depicted in the game. Those depicted are Ifalna, her daughter, Aerith Gainsborough, and the spiritual manifestation of another within the Temple of the Ancients. They look identical to regular humans, but are deeply spiritual in nature. According to Sephiroth, regular humans were Cetra who forsook their migratory nature to form permanent settlements millenia ago.

Storyline
The migrations of the Cetra were a Planet-reverent pursuit of the fabled Promised Land, one conducted by traveling from one area to another and cultivating life as they went. The Cetra had the unique ability to commune with the Planet, an ability which regular humans lost once they gave up their close relationship with the Planet in favor of leisure and convenience. Cetra also had the ability to guide the flow of the Planet's spiritual energy, this being the means by which they were able to cultivate life on the Planet's surface.

They were on the planet long before the events of Final Fantasy VII and long served as its caretakers until their race was nearly reduced to extinction by the extraterrestrial entity known as "Jenova." Jenova arrived on the Planet some 2000 years before the events of Final Fantasy VII, crashlanding on the northern continent within a meteorite. The impact site was a massive crater that would come to be known in later times as "the Northern Crater," a wound to the Planet that would not be healed even by the time of the game's beginning.

What was already a bad situation became all the worse once Jenova emerged from its impact site and approached the Cetra settlements, gleaning their memories and emotions from their minds and adopting the forms of their dead relatives in order to get close to them. It was then that it released a virus upon the Cetra (in actuality, its own cellular material), a substance that drove the Cetra mad and caused them to transform into monsters. A small band of unchanged Cetra united and mounted on a final assault on the being they referred to as "the Calamity from the Sky," surprisingly managing to defeat it and seal its body in the Planet at Jenova's point of arrival, the Northern Crater. Jenova itself would later be excavated by Shinra Electric Power Company scientist Professor Gast and be mistakenly identified as a Cetra.

Many fans incorrectly believe that the Cetra are actually an alien race which migrates from Planet to Planet. This is due to translation issues and a failure to clarify the interchangability between "land" and "planet." In actuality, the game's script states through Aerith that the Cetra were born on the Planet of Final Fantasy VII, and that -- upon death -- they will return to the Promised Land. This is an allusion to the return to the Lifestream, it being the Promised Land of the Cetra. This concept is confirmed by the Maiden Who Travels the Planet novella in the Final Fantasy VII Ultimania Omega Guide.

Ifalna was among the last known living Cetra. Her daughter Aerith was the very last. Because Sephiroth killed Aerith at the Forgotten City while she was praying for holy, the Cetra are now extinct.

Trivia

 * As can be seen in the painting depicting Jenova's fall in the Temple of the Ancients, Cetra civilization was apparently similar to Ancient Egypt.