You can't assume that everything has been changed from the status quo of the real world until we're given reason to either, or it's impossible to view a fantasy story. If you assume that people cannot fly, that they cannot breathe underwater, that they have the same tolerances to heat and cold that we do, then things are a lot more logical and run a lot more smoothly.
Who says I’m assuming everything? Were I to do that, then the second the game loaded I would be dumbstruck by the fact that the game uses the same colors, forms, materials, and objects as the real world. When immersing into a fantasy world, It’s best to view things “as they are,” not “as they should be.”
And, honestly, in Fantasy stories, how often is the status quo different with the ordinary people? The people who have magical powers and can do super human things usually have explanations behind them explaining why they can do these things. Plot elements like "They're the child of magical beings/the child of a magical being and a human," "They're an alien," or "They're using these shiny magical rocks."
None of the above really conforms to the “status quo” of the real world, though, as there are no magical beings, no aliens (that we know of), and no shiny magical rocks. So there still persists the question of “how do those work?” Furthermore, the settings themselves, being alternate universes, throw out just about all the scientific and idealistic presuppositions that attach themselves to the things we observe.
What I'm suggesting is that those are one and the same.
If that were true, then all the members of SOLDIER, and Sephiroth himself would have mutated into monsters. You’re saying Jenova’s virus went in and mutated Sephiroth when he was an infant. Why then does his Jenovian anatomy still develop into that of a human’s? Doesn’t the Jenova virus mutate those it infects into monsters?
Any biological material ever assimilated into or ever part of the creature would qualify, wouldn't it?
But Sephiroth was never a part of the Jenova cells Kadaj ingested. Jenova had cells cut from her, placed into Sephiroth, and then later on Jenova had cells cut from her and placed into Kadaj. Sephiroth only controlled Jenova with his will, he never became her physically.
When I say this, I mean it the way Squall of SeeD did (which sephiroth5086 mentioned): he is the evolved -- or, more accurately, mutated -- Jenova.
Again, that’s an interesting interpretation, but I don’t think it’s definitive. I’ve read Squall of SeeD’s analysis, and his reinterpretation of Sephiroth puts far too much emphasis on the destructive aspect of Sephiroth’s character (saying it was just an extension of Jenova’s destructive intentions) without taking into the account the transcendental, will to power aspect of his character. Yes, Sephiroth wanted to wipe the world out, but only as a means to an end; a means to become a god.
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