Weakness payment

Albus Dumbledore: "Oh, surely not. So crude."

Harry Potter: "What is it, Professor?"

Albus Dumbledore: "I rather think that we are required to make payment to pass. [...] Blood, if I am not much mistaken. [...] The idea, as I am sure you will have gathered, is that your enemy must weaken him or herself to enter. Once again, Lord Voldemort fails to grasp that there are much more terrible things than physical injury."

— Albus Dumbledore explaining Voldemort's protection on the Cave to Harry Potter

Albus Dumbledore gaining entry into the Cave with his blood

A payment of weakness was the way of gaining entry to the inner part of the Cave. It consisted of weakening the person who wanted to gain entry in any possible way, and was created by Tom Riddle in his early teenage years in the 1930s.

History

In 1979, Regulus Black had begun to have doubts about serving as a Death Eater, but was reluctant to act. One day, Voldemort asked Regulus for the use of his house-elf, Kreacher. Voldemort used Kreacher to test the defences around his locket Horcrux, leaving him to die afterwards. Kreacher was able to escape using house-elf magic, and told Regulus of what had happened. This led to Regulus's defection and he travelled to the Cave to replace the locket with a replica. He had to get past the passage which required that he weakened himself.

On 30 June 1997, Albus Dumbledore and Harry Potter Apparated to this cave to break into the place where the Horcrux was hidden. In order to get inside, Albus Dumbledore used his knife to cut his hand open and use his own blood to get past the passage and into the inner part. He noted this method was another sign of Voldemort's inability to understand there were more terrible things than physical injuries. Harry tried to offer his blood instead, but Dumbledore declined, believing the young man's blood was far more precious than his own. Later, when the two departed with the locket at hand, Harry used the blood that was dripping out of him from a scrape to serve as payment for the doorway.

Behind the scenes

• This may be similar to the blood payment that Bellatrix Lestrange used to protect her lock on her and her sisters' keepsake box.
• This may also be similar to the door in Slytherin's Scriptorium, which required one to use the Cruciatus Curse on somebody else to gain access.

Appearances

• Harry Potter and the Half-Blood Prince (First appearance)
• Harry Potter and the Half-Blood Prince (film)
• Harry Potter and the Deathly Hallows (Mentioned only)