As we all know in this book LV comes back into power he is in a new body and is as strong as he was before when he reeked havoc in the wizarding world.

He used the bone of his father, flesh of the servant and BLOOD of the enemy (harry)

LV has soooo many enemies that would be way easier to get to then harry why not use their blood?--- because LV has a thirst for power and anything he belives will give him more power he will do. LV believes that if he uses harry's blood the one who "vanquished" him before he will be more powerful than if he would use Dumbledore's blood lets say.

Voldemort's thirst for power will ultimately be his demise.

when harry told DD what happened and that LV can touch him again DD for a split second has a look of triumph. WHY?

because he knows that by using harry's blood he has given harry ( a wizard whos skills cant even get close to LV or snape for that matter) a chance.

how? i have no idea but i know that harry can kill LV because of this sill mistake.

We know that Voldemort used three things to become re-born:

"Bone of the father, unknowingly given",
"Flesh of the servant, willingly given" and
"Blood of the enemy, forcibly taken".

Harry's blood formed a part of the process of Voldemort's rebirth, preventing the terrible effects unleashed by his murder attempt in 1981.

Voldemort felt he need Harry's blood for this task and Harry's blood ONLY. When Wormtail tells Voldemort it can be done without Harry. Voldemort tells wormtail that he has his reasons for wanting to use Harry's blood and not that from any other witch or wizard.

I belive that the use of Harry's blood will eventually prove to be Voldemort's undoing. Voldie believed that he was doing something that would only benefit himself. However, I believe this was another grave miscalculation on his part because using Harry's blood will aide Harry more in the end.

When Harry was telling Dumbledore about how Voldemort had removed the charm over Harry, Dumbledore had in his eyes a look of triumph. Dumbledore seemed to know something unknown by both the reader and the majority of magical practitioners, something we won't learn until book 7.

Voldie's plan seemed to have worked so far. By using Harry's blood in his re-brithing has given Voldie the ability to touch Harry. But he now also share's part of Harry's protection.

However we can not forget about Lily! Lily's scrifice was made out of sheer love - the one emotion that Voldie hates and fears above all others - the one thing he always under estimates the powers of!

The only power that Voldie fears, the only power than he can not defeat, runs through his veins.

Now, JKR has been refering to Harry's looks through out the entire series. Almost everyone who meets Harry comments on this.

Most recently was Slughorn:
In 1999 JKR said:
Since we haven't found out the reason why Harry having Lily's eyes are so important yet it is safe to say it wont be relieved until book 7.

I believe Lily's eyes are important because it has something to do with the battle inside Harry between Love & Hate.

If Harry is a horcrux he has been living with a small piece of Voldemort's hate filled soul in his body for most of his life. Because of this Harry has become like Voldemort in several ways:

1) he speaks and understands parseltounge.

2) We know that Harry looks like his father but he also looks like a young Voldemort!!

CoS page 243:

Quote:

A boy of about sixteen entered, taking off his pointed hat. A silver perfect badge was gliniting on his chest. He was much taller than Harry but he too, had jet black hair.

CoS page 317:

Quote:

There is a strange likness between us afterall. Even you must have noticed. Both 1/2 bloods, orphans raised by muggles. Proabably the onlt two parselmouths tocome to Hogwarts since the great Slytherin himself. We even look something alike...

Look by the way is in italics in my copy of the book!

3) they share a magical conenction to each other through Harry's scar.

Harry's looks may be genetic only. But it is curious how similar Harry and the young Voldemort look a like. Having Voldemort's soul inside of him for all of these years may have influenced Harry's development.

Harry has remained good & full of love dispite this influence. He has never been tempted by the Dark Arts. Having Lily's eyes could siginfy that Harry is filled more with Love than the hate of Vodlie's horcrux inside of him. That the love inside of Harry will beat back the hate.

That combined with Lily's love magic that flows in Voldemort's veins will be Voldie's downfall. I believe in the final showddown not only will Vodlie be attacked from the outside but that Lily's blood runnning in his veins and her love will attack him from the inside. Having that LOVE shine through Lily's eyes in his final battle will be the edge that Harry needs to bring down Voldemort once an for all.

Voldie will once again be defeated by "that silly girl's" protection of Love. Which Voldie would have once agian have brought it all upon himself!

^ Sorry but I have the attention span of a squirrel and couldn't bear to read all that, so if I repeat something this person said I'm sorry.

I think that DD had a look of triumph because (spoiler alert for book seven) he realized the mistake that Voldy made. DD knew that Harry had to die in the end, but since Voldy took Harry's blood he made sure that Harry was still tied to him, so even if he (Harry) did die, he would still be tied to life with Voldy, so he would live. Confused? Read the Chapter "King's Cross" in the 7th book and it should support my theory.

Im sure this was answered on a FAQ on JKR website, but i cant find it.

It something like, to be more powerful and make sure that the potion worked he had to use his worst enemy.
And i think it had somehing to do with Lilys protection.

Voldemort never really had a downfall in Goblet of Fire. Infact he was revitalized and all Harry had left in protection was his wands core which matched Voldemort's. What is funny about this is that if Harry did not have the conection to Voldemort through his scar the Holly pheonix feather 11 inches that matched Voldemorts core. However Harry escaping because of Priori Incantantam was not Voldemort's demise, he still lived and now his weakness could be prevented using another wand. His demise comes from mistaken ownership of the Elder Wand

I think that glint of triumph in Dumbledore's eyes means that Voldemort only has one option to him now if he wants to save himself from certain death. He must feel remorse. And knowing Voldemort won't ever feel remorse for the things he has done gives Harry that edge. I think it deals much more with the horcruxes than we originally thought. To put your soul back together, you must feel remorse. And to save yourself, you must feel remorse. So Harry has a distinct advantage here, because he can feel remorse.