Here's my thoughts on it:
Jenova is an alien parasite that travelled to the FFVII Planet. Once there, she encountered the Cetra/Ancients, who were a species that could communicate with and understand the Planet. Jenova tried to wipe them out in her plan of feeding off of the Planet, but the surviving Cetra managed to seal her away in a geological stratem.
Thousands of years later, Shinra Inc. found her and mistakenly thought she was an Ancient. In an attempt to create a living Ancient, her cells were injected into Sephiroth while he was still in the womb of his mother. Because Jenova's cells were injected into Sephiroth while he was still developing, they're a fundamental part of his final physical makeup. As a result, he has the ability to exert a form of control over others who were injected with Jenova cells, but only if they're weak minded.
Also, originally humans and Cetra were the same species, but the ancestors of the current humans stopped travelling the planet with the other Cetra and just settled in one place. Since they stopped caring for the Planet, they eventually lost their powers and became what we would consider normal humans.
Wow, way to have nothing new to say. Seriously, that was all explained in the game, pretty much. You havent come up with anything new here.
Newsflash:
I'm a Cetra. Worship me.
Newsflash:
FFVII has a ****ty storyline that was filled with so many potholes and so convoluted that it doesn't even make sense. Thus, why these theories are always stupid. Don't try and make sense of it. Just read the book that was released that explains it completely (or from what I've heard).
Are you trying to steal my glory. >:O
Yeah, FFVII wasn't the greatest...but I still found it highly enjoyable to play, despite how ****ed up the storyline was. It was just fun to play.
When I first read this thread... I was wonder, "What in the name of **** is he talking about?"
The moral of the story is that FF7 was easily the worst in the series, and by my obserPLAY XENOGEARS NOW.
All pot-holes were language related. The japanese version doesn't have as many, if any at all. And that isn't a theory, Gamer is right. That's how it happened. There's also some contributing info hidden throughout the game to explain how everything tied in(Except Yuffie.).