During their teenage years, Albus Dumbledore and Gellert Grindelwald made a blood pact where they swore an oath never to fight each other - presumably as a fail-safe to ensure no rift were to set them apart in their grand endeavour to ignite the revolution between the magical and the non-magical aggregations wherein ...
Why did the blood oath break in secrets of Dumbledore?
Seeing as Credence was Aberforth's son, the pact broke when the Dumbledores' blasts connected with Grindelwald's blast. As Albus would rationalize later with Newt, his spell was meant to protect, and it canceled out Grindelwald's, which was meant to kill a Dumbledore.
Did Snape make an unbreakable vow with Dumbledore to protect Harry?
In Harry Potter and the Half-Blood Prince, Severus Snape (Alan Rickman) undergoes an unbreakable vow with Draco Malfoy's mother, Narcissa Malfoy (played by Peaky Blinders' Helen McCrory) where he promises to protect Draco until the boy kills Dumbledore but will kill Dumbledore himself if he fails.
What would happen if Snape broke the unbreakable vow?
Harry Potter and the Half-Blood Prince Ron and Harry discuss the spell. An Unbreakable Vow is a magical spell of unknown incantation, in which one witch or wizard makes an oath to another. If either of the two break their terms, they die.
He though of himself as the greatest, most powerful most awesomest wizard who ever wizarded. He had no need to have his minions make unbreakable vows because he was so confident that if any of them did try and betray him, their deaths would be swift and very very painful.. No vow was needed in his mind.
Why Snape Agreed to an Unbreakable Vow (and to Kill Dumbledore) - Harry Potter Explained
Why did Snape accept the unbreakable vow?
He promised to protect Draco Malfoy from harm and guide him whilst he attempted to perform the task the Dark Lord had asked him to do: to kill Albus Dumbledore. Snape was actually a double agent working for Dumbledore, who requested Snape to kill him anyway to spare him of a painful and humiliating death.
Family. Snape's family background is mostly shown in flashbacks during the course of the last three novels. Snape was born to Eileen Prince, a witch, and Tobias Snape, a Muggle, making him a half-blood (hence the name, "Half-Blood Prince").
Despite her beliefs and her family's close ties to Lord Voldemort and the Death Eaters, Narcissa never joined the organisation herself, nor received the Dark Mark. While she treated most people coldly, Narcissa was very loving towards her family as well as devoted to them.
While through most of the series Snape seems to be horrible to Harry and possibly trying to get him into Voldemort's hands, it's revealed at the end of the series that Snape was actually helping watch out for Harry.
Fred and George once tried to make Ron take an Unbreakable Vow as children. Shockingly, this would have meant certain death if Ron hadn't fulfilled whatever it was they were trying to get him to promise – we can only imagine what they'd chosen!
He hid them using the only thing that would work against Voldemort. He used Fidelius charm and after that even secret keeper was to be protected using that as Sirius said in PoA. The plan failed because wormtail who was their secret keeper betrayed them.
Despite Snape killing Dumbledore, it is learned that they had a special agreement for him to do so. When he died, it was revealed that his deep strong love for Lily Evans caused him to redeem himself, joining Dumbledore's cause for her protection (and, after her death, that of her son) from Lord Voldemort.
Voldemort seduced Snape to his cause and Snape did betray Lily and James to him when he told Voldemort a part of the prophecy connecting him and Harry. It is for this reason that he went to kill the Potters, and Snape never forgave himself for that.
The simple answer to that is that Voldemort was in hiding so Dumbledore would have had to abandon his job to track him down, and he was needed to protect Harry and the young wizards from ministry and other influences, it would take prodigious skill to duel him and win (Dumbledore fails to do this OOTP, for instance.
By this point, Credence was slowly dying as his Obscurial nature poisoned him, the real reason that his phoenix had come to him, something that Dumbledore had recognised after having seen something similar with his sister Ariana, who was also an Obscurial.
At some time after the end of the Global Wizarding War, Newt and Tina marry. Newt creates the Werewolf Register and the Ban on Experimental Breeding. Newt also works for the Dragon Research and Restraint Bureau. In 1979, he is awarded The Order of Merlin - Second Class for his services to magizoology.
Why didn't Snape tell Harry he was protecting him?
Snape even said that he didn't want anyone to find out that he was protecting Lily's child, “especially Potter's son” (pg. 679 of Harry Potter and the Deathly Hallows) because of his hatred for James. Instead of providing Harry a safe haven from his abusive home with the Dursleys, he tormented Harry over an old grudge.
Snape's hatred towards Harry in the Harry Potter series was fueled by his unrequited love for Lily, which he couldn't move on from due to guilt. This adds complexity to Snape's character and explains his treatment of Harry.
In fact, Lucius' own support to Voldemort is revealed to come only under some form of duress, which is likely Narcissa's Veela Allure. When Lucius turns on Voldemort due to the reveal of his Horcruxes, Narcissa divorces him, taking 75% of Malfoy's wealth with her.
She married Rodolphus Lestrange after leaving Hogwarts "because it was expected of her" to marry a pure-blood. However, Rowling stated in an interview that Bellatrix truly loved Voldemort.
Although he wasn't turned into a werewolf, he did develop some wolfish tendencies such as a liking for very rare steaks. He married Fleur on 1 August 1997, although their wedding was disrupted by the arrival of Death Eaters following the fall of the Ministry of Magic.
Under the influence of her father, Dolores grew up despising her mother and brother for their lack of magical abilities. She was sorted into Slytherin House at Hogwarts School of Witchcraft and Wizardry and hated her time at the school due to never being given any positions of power.
For the second time in Voldemort's life, the unforgivable curse rebounded on him, as the Elder Wand wouldn't kill its master. Since Harry and his friends had already destroyed all of Voldemort's Horcruxes, this finally ended Lord Voldemort's life, with Harry finally defeating the Dark Lord.
