I just wonder that during his first few years at Hogwarts, Harry could have died in a Quidditch match, or by any accident in the Muggle world, or even been killed using a knife by anybody. Would that affect the piece of Voldemort inside him?
Firstly, could he have died?
Then, what would happen? Dumbledore said that "it was 'essential' that Riddle killed Harry" but what if he died before that? Did this mean he was immortal except for Voldemort killing him?
There is nothing indicating that Harry's life was protected by anything out of the ordinary. That's not to say he wasn't protected - Dumbledore took a keen interest in him and the rest of the staff at Hogwarts worked hard to keep all the students safe. It's notable that Hogwarts hadn't had a student die for decades, yet it bordered (and occasionally sent first years INTO) a forest filled with giant spiders, centaurs, etc. It had a tree on the grounds which could and would pummel anything in reach into submission, with no indication that it would stop when the subject ceased moving. The staircases within the school similarly posed normal dangers - they frequently moved with students on them, would have steps disappear, etc.
The students, therefore, were under some serious protection just to stay alive at first.
That said, there's no possible way that Harry could have died before facing Lord Voldemort.
From an out of Universe perspective, it would make for a terrible book.
From an in-Universe perspective, neither Harry nor Voldemort could die except by the other's hand. Prophecies, in the HP Universe, cannot be wrong. They can be misread, misconstrued, misrepresented, or otherwise turn out entirely unlike they were expected to, but they will always make sense, once fulfilled, to the person who originally heard them.
The prophecy that foretold Voldemort's downfall (which could have applied to Neville, had Voldemort chosen to mark him instead) was clear on one point: neither Voldemort nor the child he marked would die except by the other's actions.
The prophecy states:
"The one with the power to vanquish the Dark Lord approaches ... born to those who have thrice defied him, born as the seventh month dies ... and the Dark Lord will mark him as his equal, but he will have power the Dark Lord knows not ... and either must die at the hand of the other for neither can live while the other survives ... the one with the power to vanquish the Dark Lord will be born as the seventh month dies ..."
(emphasis mine)
Ergo, it was certainly possible for Harry to die a natural death while a Horcrux, but it was already known that he wouldn't.
This is addressed somewhat in an interview with J.K. Rowling. She goes off on a tangent a bit and doesn’t directly answer the question, but it seems like she’s saying he could have died naturally. However, the piece of soul would only be destroyed if Harry actually died. (She says his body would have to be destroyed but it seems more likely that she really meant he had to die: his body isn’t at all damaged, much less irreparably damaged, when the Killing Curse hits him and the soul piece is destroyed.)
SU: So, can I ask this? This is kind of a random question, but if Harry had this Horcrux in him, sort of, would he actually have died, say, when the dragon could have killed him, or when he was falling during Quiddich, or anything? Could he actually have died?
JKR: Well, you’ve got- if his body had been irreparably destroyed. (SU: Yeah) He has to die to get rid of that piece of soul. His body has got to be irreparably damaged. So a lot of people asked, and I think I’ve answered this since, but a lot of people immediately said, having finished Hallows, (gasps) “But then, that means in Chamber of Secrets, when he was pierced by the basilisk…” (SU: Oh, right) but no, no, no, no, he didn’t die! He didn’t die. (JN: Yeah) That was stated right in the beginning with the Horcrux, the receptacle has got to be destroyed. His body wasn’t destroyed! He got a bit poisoned, and then he got the antidote, immediately. So that’s not going to drive out this piece of soul. Sorry if I sound frustrated, but occasionally…
- PotterCast (Dec 23, 2007)
The first part of what she says certainly seems to be implying that he could have died - though it’s possible she’s saying his body would need to be irreparably destroyed before that could happen. Even if that is the case, there are definitely ways he could be irreparably destroyed. If he’d been eaten or incinerated by the dragon in the Triwizard Tournament, for example, that wouldn’t be reversible even by the most powerful magic. The piece of soul certainly didn’t seem to be making him immortal or immune to death - the most it may have done is made it harder for him to be killed.
Harry could die before the Dark Lord killed him, but in any case where that happened, Harry would almost certainly stay dead. Since Dumbledore wanted the Dark Lord to be defeated but didn’t actually want Harry to die permanently, he preferred letting Harry sacrifice himself and come back to life. Throwing Harry into Fiendfyre or letting a dragon kill him would result in permanent death, with no chance Harry would live. Dumbledore knew when the Dark Lord took Harry’s blood it tethered Harry to life while the Dark Lord lived - but Harry likely could only live if he still had a body to live in. So, letting the Dark Lord kill him with Avada Kedavra was much preferable to ensure Harry’s ultimate survival.
"You were the Horcrux that Voldemort never meant to make."
Afterlife-Dumbledore in Harry's King's Cross Station fantasy
Yes. Harry was a Horcrux, which is interesting, because he was never really in any danger - except when he was bitten by the Basilisk, and when he was being chased by the Fiendfyre. He could have been killed by either of those things, or by the sword of Gryffindor, but otherwise he was completely safe. Same for Nagini.
When Voldemort killed Lilly Potter, part of his soul latched itself onto Harry, the only living thing around, creating a horcrux. Perhaps, if Harry had died, (not at the hands of Voldemort) that part of Voldemort's soul would then leave Harry's body and latch itself onto the nearest living thing it could find, again, creating another Horcrux.
