Killing tears the soul apart redux. Luna and sacrifice

[vmonte]

No: HPFGUIDX 139512

Lupinlore:
That is one scenario, and it may well come true. However, it does
not include one crucial piece of information, what was the "gleam of
triumph" we saw in DD at the end of GoF about? Surely not a
realization that Harry is a Horcrux and will have to die.

Let me offer a modification of your scenario, simply as a thought
experiment. Let's say Harry IS a Horcrux, and that DD had suspected
that for some time. Okay, but DD has said that putting a part of your
soul in a living, thinking creature has great dangers. Maybe in
using Harry's blood to effect his return, Voldemort unwittingly
created a "reverse conduit" between himself and Harry. That is, he
created a connection through which Harry might be able to force the
soul shard out of his own body and back into Voldemort's, thus in
effect "destroying" the final Horcrux without literally destroying
himself. This would explain the "gleam of triumph" remark from GoF
AND the "in essence divided" remark from OOTP.

vmonte:
Yes I've mentioned something similar in my previous posts. The idea
is that Lily's blood is weakening Voldemort. And that the protection
Lily gave Harry (along with Harry's life experience--friendship,love) 
has somehow transformed the horcrux. So that when the time comes 
Voldemort will take back the horcrux and it will kill him.

I think that Harry will sacrifice himself. But...     

If Voldemort cannot bear the love that resides in Harry's head can
you imagine what a "love horcrux" will do to him?

It would make sense that Lily's gift would act in very much the way 
that Dumbledore idea in the PS did. Harry's sacrifice will cause 
Voldemort's weapon to backfire on him. 

It all goes back to the Philosopher's Stone. The person that wants
the horcrux (the Stone) but does not want to use it for evil, will be
able to get the horcrux.

Vivian