Ilya was designed and trained from birth to be a Grail, whereas Sakura is a normal human being who had chunks of the previous Grail embedded in her. Thus, Ilya is able to retain the spirits inside her without too many issues (although she does have to "turn off" some of her human functions), whereas with Sakura it leaks out (resulting in the Shadow) and, eventually, corrupts her.
And, yes, Ilya is aware of Sakura's status as a Grail, at least in HF. If Shirou doesn't get enough Ilya points, then she shows up at his house on about day 7 (before Shirou is even aware that Sakura is a magus) and turns him into a doll to use against Sakura. It's not 100% clear
exactly when she works it out, though, she might well not know until Sakura is activated (and, potentially, until she absorbs a soul that Ilya herself should have received).
@ Cherry:
Sorry it took so long to reply.
Eh, what? Where did you get the idea it was "filled with shadows" from?
Don't trust me on that, since I vaguely remember reading something to that effect on the wiki. "Taking it into the shadow realm and spearing people with the shadows" or something.
Ah, OK.
Well, it seems plausible that she could do that, but I don't think her shadow realm is
necessarily full of shadows, and nor do the shadows only exist there.
But the soul isn't "destroyed" in the process of doing so, since the eventual result of the Grail War would have been the souls of the heroes returning to Akasha and, in the process, punching a hole that could be opened wider to allow the magus performing the ritual to get there.
So the reason the Heroic Spirits are retained is so that when there are enough of them, the effect of 6/7 of these huge souls getting back to the Root at once would open a big enough hole for shit to happen? If so, then I've been misunderstanding the process this entire time.
Actually, to open the path to Akasha, it needs all 7. But, yes, that's the basic principle.
However, I believe that precisely
none of the participants in the fifth war both know and care about this. Ilya probably does know, but since she's the Grail she cannot do it herself, and Zouken may well know but couldn't care less since he just wants immortality. Rin doesn't know because her father died unexpectedly (because he was too damn arrogant to realise the possibility of death in a seven-way-war where the losers are usually killed...) and thus never thought to teach her all this stuff.
Yeah, I'm not sure you even could "dissect" a soul. I believe the soul is actually indestructable.
IIRC, when a person dies their soul returns to Akasha and is torn apart, wiped of all information and the bits are reused. Souls are definitely indestructable, but they can seemingly be divided and wiped clean.
ATTW, it says that the soul is indestructible in the material realm, but that the soul usually resides somewhere else that's between the Root and "reality", meaning that someone could conceivably start ripping it apart if they could access this space-between-spaces (lol).
Hmm, yeah, that's possible.
Yes, Reality Marbles were always about forcing the reality of your persona/soul to your surroundings.
Or more like (because of limitations) that a Reality Marble materializes the most predominant concept of your soul.
This makes them unpredictable thus dangerous. Probably why the Mage's Association has a ban on these.
Actually, this isn't really true, as far as I can tell. The main reason for having a ban on Reality Marbles is that the heads of the Association don't have one, and thus they dislike others having them. Plus, since they're not something you can learn or pass on to your kids, they don't fit with the whole "improve your family line" orthodoxy that the Association holds to.
And to answer Mike's question, no I seriously doubt that vampirized humans are given a new soul.
It's more like a spiritual infection. The soul which is seemingly unalterable does suffer changes in the process.
It's kind of like how Archer's arm gradually invaded both Shirou's body and soul. Killing him and his memories as time went on.
And I remembered things wrong with Dead Apostles. They don't have everlasting souls. The reason why they need to consume blood is to refill their corroding spirit with fresh human DNA and souls. So basically they are also eating souls.
Of course by constantly drinking blood, Dead Apostles souls can technically last forever. Because it renews itself by the sacrifice of human souls.
And apparently, with age, Dead Apostles learn how to minimize the degradation of their souls thus requiring less blood.
Yeah, I guess that makes sense.
It also explains why they get less and less human as they age. A new vampire like Sacchin or Sion can still be basically good, but an older one will invariably end up eating indiscriminately without caring for others.
As for the Magus being a different race, I seriously doubt that.
Not from the biological standpoint, at least. Magi and "regular humans" are still capable of having an offspring.
Well, that doesn't imply they're not a different race. Biologically-speaking, "race" means a subdivision of a species which has clearly-identifiable traits that other members of the species don't have, members of which usually don't interbreed with members of other races (because of either physical seperation or sexual selection), but are still capable of breeding with the rest of the species. So, in that sense, magi actually
are a different race from normal humans (interestingly, according to the biological definition of "race", the normal human population does not have them, since we inter-breed too much for them to form).
But the capability to cast magic seems to be an ancient gene. If it's even expressed in the genes at all. Maybe it's merely an imprint which exists in the soul and then expressed from there to effect the body.
Otherwise a more savvy magus might've used genetic engineering to create an offspring with the best magic qualities.
I also doubt that things like elemental attribute are something connected to the magus' genes.
Of course this is just speculation on my part.
Maybe magi are just so averse from science that they don't even know what the advances of genetics can do.
And in light of their oppressed feeling because of technology, we can understand them.
Well, it clearly is in some sense "genetic", because powerful parents have powerful kids. Still, it can't be as simple as a "magus gene", because, for example, Aoi is not herself a very powerful magus, but possesses a trait that makes her
children powerful magi. Which doesn't really make sense from a purely genetic perspective.
Also, the affinity is definitely genetic, because Sakura needed substantial alteration to make her into a Matou magus. Her natural abilities are as a Tohsaka.