Before you can discuss that, you have to clarify who you mean.

I've played FF7 many times over, and what I've gathered is that when the story begins with AVALANCHE destroying the No. 1 reactor, at that point in the story, the man Sephiroth is dead. He died when he fell into a Mako Reactor, after putting a large sword into Cloud. My understanding is that Sephiroth was a powerful man, capable of doing things that most humans could never do. But he was still a mortal man with limitations almost identical to the average human.

If that's the case, how does one explain the Sephiroth you see in the game at various times, like on the boat from Junon or in the Forgotten City, descending from above with the afforementioned large sword?

That being is actually Jenova, I think. And that's the Sephiroth that you chase after. That's the one who can fly and stuff. Humans can't hover like that. The real Sephiroth was no exception.

So..... The real human Sephiroth who died a while ago wasn't a bad guy initially. He learned where he came from, and it drove him all kindsa crazy. His crazy angry-at-the-world rampages ended with his death, in the Mako Reactor.

But the Jenova Sephiroth is totally different. That one is always babbling on about the planet and the Promised Land and such. It's not angry at the world like the real Sephy was. It is simply doing what it feels is right. That Sephiroth has nothing but good intentions in that he is setting things the way they should be.

So to call him a good "villain" seems stupid because someone with intentions like that isn't very "villainous". In fact, upon completing the game, you're left to think that perhaps Sephiroth/Jenova was right. Perhaps the world needed these things to happen like Meteor and such to make things right. According the Sephiroth, the humans were responsible for the disappearence of the Cetra, who rightfully should've been living on the planet. If that's the case, that would make Sephiroth/Jenova the good guys and Cloud and his gang would be a side plot of sorts. I think Cloud's not concerned with the justification of the humans or any of that. I think he's concerned with stopping a world threatening catastrophe at the moment, and then he'll sit down and figure out the philosophical and moral rights and wrongs after the eminent threat is gone.

I think I recall reading that Sephiroth is biologically the child of Hojo and Lucretia. I do remember something about Hojo messing with him while he was still in the womb. But how does Vincent fit into that scenario? And what about Professor Gast? I know he was this brilliant researcher, but what did he uncover? Or what was he working on? I know it relates to the Cetra, because I seem to remember him being married to Ifalna, whom I seem to remember being Aeris's real mother.

And while I'm getting all FF7 philosophical, I have a few questions that I haven't gotten figured out yet. Did Nibelheim really burn down? If so, why was in totally good shape when you arrive there in the game? And why does no one there recall the event taking place? And if it didn't burn down, then why does Cloud think it did? And why does Tifa think it did? When Cloud tells the story at the Kalm Inn, Tifa doesn't object to it and seems to sit silently as Cloud talks about Sephiroth burning down a city.

So that brings me to my next question. Was Cloud really an experiment? I know he probably got the Mako Treatment like other guys in SOLDIER, even though I think he was never really in SOLDIER. But was he really part of Jenova like Sephiroth was? Did Hojo or whoever actually inject him with Jenova to try and create a superhuman kinda guy? He did go totally crazy when he was with Zack heading to Midgar, when Zack died. I'd think that might be a side effect of the Jenova infusion thing. But that would mean that he didn't really grow up in Nibelheim.

Or maybe he grew up in Nibelheim, left to join SOLDIER, and then they did their weird stuff to him and it made him all crazy.

And why does Cloud think that he was Zack in a lot of his stories? You find out that he was a Shinra guy, but not in SOLDIER. So how did Cloud get to thinking that he was Zack in all those stories?

When Sephiroth, Zack/Cloud and two Shinra guys go to Nibelheim (during the Kalm Inn story), Tifa talks with Cloud during that visit, and even guides them through Mt. Nibel. You learn later that Cloud was there for that visit, but Tifa never knew because he had his helmet and mask on the whole time.

And the Weapons? What's their deal? Are they the planet's self defense mechanism? They come out when someone is messing with the Mako levels and just level the world, Mana Beast style?

And finally, why is it that when you use "Climhazzard" on Palmer (during the fight in Rocket Town), Cloud jams the end of the sword directly into Palmer's crotch before leaping into the air?

So there you have it. All the weird confusing stuff that came to mind. Even after several play-throughs, I still don't get a lot of that stuff.