Worse still, Black was heading for Hogwarts to kill Harry. He wanted to avenge the death of 'You-Know-Who' - evil Lord Voldemort - whom Harry had killed to avenge the death of his parents (see earlier Harry Potter books).
Asides from his Headmaster portrait, which is only a caricature, the nature of Nigellus Black's relationship with Harry Potter comes about primarily through his lineage. Nigellus is an ancestor of the pureblood Black family, and his great-great-grandson Sirius took on the role of Harry Potter's godfather.
He knew that by this time Harry should be thinking that serius has betrayed his parents. And for this reason he was searching for harry. He wanted to tell the truth and want harry to know that he was not an enemy but a friend.
After leaving school, Sirius fought against Voldemort, eventually joining the Order of the Phoenix. He remained close friends with James and eventually attended James and Lily Evans' (now Lily Potter) wedding as their best man. When their son, Harry, was born, Lily and James named Sirius as Harry's godfather.
And this proved to be the most fatal mistake of Sirius's life. Peter, it turned out, was a coward who folded the instant Voldemort turned an eye toward him. Fearing for his life, he betrayed the Potters, leading to their death and the orphaning of baby Harry.
'I persuaded Lily and James to change to Peter at the last moment, persuaded them to use him as Secret-Keeper instead of me ... I'm to blame, I know it ...' It wasn't Sirius who betrayed the Potters to Voldemort, but he did persuade them to make Pettigrew their Secret-Keeper.
Avada Kedavra (the Killing Curse) was not vividly identified as the spell that hit Sirius Black. According to the circumstances mentioned in the book, Bellatrix Lestrange most likely used a stunning spell against Sirius.
In universe its because he was framed by Pettigrew so people believed he was a death eaters and sold Lily and James out.
Sirius Black
He was then subsequentally burnt out of the family tapestry for daring to be different. Next up: he was imprisoned in Azkaban for over a decade for the murder of 12 Muggles and his former best friend Peter Pettigrew, who actually framed him and faked his own death.
'Because I hated the whole lot of them: my parents, with their pure-blood mania, convinced that to be a Black made you practically royal . . . my idiot brother, soft enough to believe them . . . that's him. ' ... 'He {{Regulus}} was younger than me,' said Sirius, 'and a much better son, as I was constantly reminded. '
Sirius is the 'closest thing' to a parent that Harry has: he's the first person Harry thinks to write to when in trouble, he turns to him for reassurance and support in times of moral dilemma (such as when he witnessed Snape's worst memory), he trusts him within a few hours of meeting him.
Lily's blood and protection lived on and would last until he came of age. Therefore, if Harry had gone to live with Sirius while he was still underage, he would not be safe from Voldemort.
There is no doubt that Sirius loves Harry and is fiercely protective of him, but he does let his more immature impulses take over sometimes. In The Order of the Phoenix, Sirius wants to visit his godson in Hogsmeade while disguised in his Animagus form.
As other people said, it is also due to the Malfoys' arrogance, the feeling of self-importance and wealth. The Weasly family is also very poor, which may also lead to a dislike with the rich, pureblood families.
The Weasleys descend from Cedrella Black, a granddaughter of Phineas Nigellus Black. Sirius Black, Bellatrix Lestrange and Narcissa Malfoy all descend from Pollux Black (left). Note: This family tree excerpt (made using Ancestry.com) does not list the Weasley children in the correct age order.
The biggest revelation in Harry Potter and the Cursed Child was that Lord Voldemort had a daughter with Bellatrix Lestrange, who was named Delphini.
Saving Sirius Would Ruin Dumbledore's Plans For Harry
Upon looking into Dumbledore's manipulative ways and his intense plans, the most likely reason Dumbledore did not help Sirius is that the result would have interfered with his plans for Harry.
When we were first introduced to Sirius Black, he was a wanted fugitive on the run from Azkaban, convicted of the murder of Peter Pettigrew and of betraying Harry's parents. Not a good start. Sirius didn't exactly improve matters when he tried to sneak into the Gryffindor dormitory by slashing the Fat Lady's portrait.
Later on in life Marlene becomes the wife to Pure-Blood Wizard Sirius Black and the mother to their children Half-Bloods Aries, and Artemis Black. She is the sister-in-law to Pure-Blood Wizard Regulus Black, Muggle-born witch Vivienne Price and aunt to Half-Blood Renee Black.
Bellatrix Lestrange Killed her own cousin, Sirius Black: She killed Sirius (who was her cousin) during the battle at the Department of Mysteries. She was remorseless and was cackling in glee after she had murdered Sirius.
No one knows the truth about Sirius Black yet, not even Severus Snape. At that time, he didn't know that Sirius Black was innocent. At that time, he knew what everyone else thought they knew - that Sirius was a dangerous criminal that was out to get Harry Potter and that was said to be Voldemort's right-hand.
Pettigrew defected from the Order of the Phoenix and betrayed his closest friends to Lord Voldemort when his life was threatened, showing selfishness and disloyalty at the core of his being. Even Voldemort looked at him with disdain; the only reason why he kept Wormtail alive is that he sometimes proved useful.
Harry Potter: Why Voldemort Didn't Use Avada Kedavra On Snape - IMDb. Voldemort killed Snape in Harry Potter And The Deathly Hallows Part 2 using his Horcrux snake Nagini instead of his favorite Unforgivable Curse, Avada Kedavra.
Cruciatus Curse ('Crucio')
Repeated use of the Cruciatus Curse is torture and Bellatrix Lestrange subjected the Longbottoms to such extremes of pain that it sent them insane.
Rowling let Bellatrix prove her magical prowess during the mission when she overpowered her niece Tonks and Kingsley Shacklebolt in one-on-one duels, killed her cousin Sirius by blasting him through the veil in the Death Chamber, and deflected one of Dumbledore's spells as she made her escape.