Finally, Here's the Answer to Why the Basilisk's Venom Didn't Destroy the Horcrux in Harry's Body

In The Chamber of Secrets, we saw young Harry Potter fight and defeat the memory of a former student called Tom Riddle and the dreadful Basilisk that memory had summoned. The memory died off after Harry used a fang of the venomous King of Serpents to destroy the former student’s diary; this is what we knew back then.

It wasn’t until The Half-Blood Prince that we learned that the diary was in fact a Horcrux, and the memory was a piece of Lord Voldemort’s soul. We also learned that there were only so many ways to destroy a Horcrux, and the Basilisk’s venom was one of them.

And yet one book later, in The Deathly Hallows, we discovered that Harry Potter himself has been a Horcrux this entire time since his parent had been murdered.

For many fans, this revelation raised a fairly logical question: why didn’t the part of Voldemort’s soul that was sitting in Harry’s body get destroyed when the Basilisk bit the boy all the way back in his second year in Hogwarts? This sounds like a reasonable question, and many years later, we still see many people asking it.

The short answer would be, “the vessel of a Horcrux needs to be irreparably damaged or completely destroyed for the piece of soul attached to it to die.”

The slightly longer but more coherent version will make sure that you’re satisfied with the answer.

You see, the Dark magic that creates a Horcrux does not just bind a piece of soul to an object; it sort of mends the two together. This is why it’s borderline impossible to destroy the vessel unless you use extremely destructive methods like Fiendfyre or a Basilisk’s venom: the soul and the Dark magic protect the object from damage.

It works the other way around, too, and this is where the answer lies. The vessel in turn protects the piece of soul put into it, and you can’t destroy the soul without destroying the object itself. The vessel, as we said in the short version, must be irreparably damaged or completely destructed for the Horcrux to be destroyed.

Harry was in fact bit by the Basilisk in the Chamber, and the beast's deadly venom was quickly killing him; but he didn’t die. When Fawkes, Dumbledore’s Phoenix, healed Harry and saved his life, he also healed the vessel that contained the piece of Voldemort’s soul. Hence, the Horcrux remained safe in the boy’s body.

If you just thought of a joke about how Fawkes was trying to save Voldemort to replace Nagini as the Dark Lord’s favorite pet, don’t bother: we already joked about it. Sorry, not sorry.