Yes, but it's also something he established when the series started and was held true until he left making it a foundational element that served to improve the series. His replacements have forgotten why he imposed that rule in the first place, which was to keep the series fresh and innovative and not be like Ubisoft. Honestly, FF has been going downhill since he left and also due to the merger. The expansion stuff has been pretty awful and the franchise has pretty much lost its rep as being the forerunner of the genre on an innovative level. Now they just have enough money and brand recognition to pull off good sales but its a shadow of it's former self. Sakaguchi established the artistic integrity of the franchise which has been lacking since Wada imposed franchising individual titles to make back revenue in the wake of the disaster that was Spirits Within.
I don't consider them canon, because of that rule, and because frankly all the sequel/prequel/spin-off trout is terrible and does nothing to really expand the series in a good way. Seriously people, stop buying them so SE will actually start putting effort back into their games.
Except the rules of the thread is before there power-up. In other words, Ex-Death before he obtained the Void, let alone merging with it to become Neo-Exdeath. He was still wrecking the planet without it. If we were going by full powered versions, this list would be very different and Neo-ExDeath would be in the same league as Cloud of Darkness.And if we really get technical, Neo-X-Death is not less than the Dark Cloud. It is the true form of X-Death, the soul fusion that possessed the tree but the force that controls this body at that time is the void itself that has absorbed X-Death.
He doesn't ever show up and and no reference is made in the actual story about him. You can actually bypass every reference the game makes of him. He's not important to the plot and since he never physically shows up, you can't say he's even real just because of some folk tales told by common folks. He's a myth like Zeus in VIII's world, not an active part like Etro, CoD, or the Warring Triad. It's not enough to have stories about him when there is no actual proof he ever existed or did anything. He's a myth and a clever reference to FFIII, that is all.I do not know why the question if Hyne exists plays an actual role for this. The stories about him exist and that is enough and that we know what the entirety of all sorceress power would mean, is also enough. The next questionable thing would be how much of a villain the Dark Cloud can even be called because just being a destructive force does not make someone a villain. The consequences are bad for us but that is not the same.
As for CoD being a villain, its true she's more of a force of nature but villainy is subjective anyway. I personally feel that Seymour's plan in FFX was not so terrible due to the game's cosmology and whose to say Emporer Mateus wouldn't be a good ruler? She's basically a Lovecraftian Cosmic Horror. The fact she's indifferent just makes her more intimidating for the player and the world of FFIII.