Why 4 Horcruxes left, and not 3??

[spotsgal]

No: HPFGUIDX 142149

> expectopatronnie:
> A lot of wizards can poll through an AK,

Christina:

Can they?  Who have we actually seen execute a successful AK? 
Fake!Moody did in GoF, but that was on a spider.  We know that Peter
and Voldemort have AK-ed somebody.  If we assume that the AK on the
tower was a real one, then Snape has as well (which I don't find
suprising, given the hints we've gotten about his level of skill and
power).  Look at the battle in the DoM.  Harry mentions only two "jets
of green light" and we hear *one* attempted AK (the Death Eater never
gets the second work out).  One would think that the AK spell would be
*all* the DE's would be casting.  The fact that they didn't suggests
to me that casting AK is extremely difficult.  In the battle we see
the Death Eaters using a purple slashing curse (page 792, twice on
803), a curse that blasted Luna into the air (797), stunning spells
(796, 798), a ton of red light (perhaps stunning spells also- 801,
805), tarantallegra (802), and a few instances of Crucio (all quotes
from the Scholastic version).  These are the baddest of the baddies
here- why is anything but AK's being sent around?  Casting one
requires an extraordinary amount of hatred and sadism.  Even after
Harry witnesses Bella Lestrange murder Sirius, he *still* only manages
to briefly knock Bellatrix off her feet.  And that was just in trying
*Crucio*.

> expectopatronnie:
> but only a few are able to conjure a Horcrux. 

Is there anything that suggests that horcrux-making is more advanced
than AK?  Dumbledore says that Voldemort has created more horcruxes
than anybody else, which shows that there *are* people that create
horcruxes.  Dumbledore (and Slughorn) insinuate that it's not that
people are only able to make one, but that serial killing wizards are
rare to begin with.  The only advantage in making a horcrux is a
little temporary immortality- Slughorn even says that death is usually
preferable to the sort of state one lives in after making horcruxes. 
I think that's enough to explain why all killers don't have horcruxes
(just as all people don't drink unicorn blood when they are dying).

> expectopatronnie:
> VM is less and less human with each killing, because it *ripps* the
> soul apart, regardless infinte math calculations. 

Christina:

Which was the central point of my post.  With each killing, Voldemort
ripped up his soul more and more.  Whether removing the broken soul
parts and putting them in a horcrux makes the problem worse or not,
every time Voldemort killed/made a horcrux, he was left with a smaller
portion of intact soul, which is a mathematical problem at heart.  The
more one rips their soul, the less human one is.  The less intact soul
one has, the less human one is.  The exact mathematics are impossible
to know and are irrelevant, but they explain why Voldemort became
progressively less human.  Killing is quantitative- the damage to
one's soul adds up.

Christina