Final Fantasy VII/History

Arrival of Cetra
The Cetra, also known as the Ancients, were an ancient peoples who go from planet to planet, searching for the 'Promised Land'. It is possible that the 'Promised Land' is, in fact, the afterlife; where the Cetra return to the planet. In the meantime, it seems their mission is to settle on planets to maintain and protect that planet's lifestream and to enrich the world with their knowledge. Long in the past, a group of Cetra arrived on the planet and settled amongst the indigneous humans there.

Calimity from the Sky
Shortly after the arrival of the Cetra another lifeform landed on the planet, possibly following the Cetra. Later known as JENOVA this creature appeared to the Cetra of Knowlespole, near the north crater where it had landed. It presented itself as one of the Cetra, and brought a message of peace. The truth is, JENOVA was a malicious viral lifeform - it's cells infected the Cetra of Knowlespole who died a horrible death. JENOVA and it's virus spread among the Cetra, though it left the indigineous tribes unharmed.

WEAPONs and the defeat of JENOVA
In response to the wound JENOVA inflicted upon the planet the lifestream created 5 huge monsters: WEAPON, Diamond WEAPON, Ultimate WEAPON, Emerald WEAPON and Ruby WEAPON. The WEAPONs' sole function was to destroy everything in it's path, thereby absorbing as much spirit energy as possible to heal the wound.

TBC