Sirius Black (November 3, 1959 - June 17, 1996) was known as Padfoot to his Marauder peers, due to the fact that his animagus form is a dog. Sirius also used the nickname of Snuffles when Harry Potter, Ron Weasley and Hermione Granger wanted to speak about him in public.
Sirius was a pure-blood wizard. He was the last remaining heir of the House of Black, a once notable wizarding family. Sirius' parents, Orion and Walburga, were second cousins by blood, so they were both born with the last name Black. This was one of the few ways pure-blood families could continue to be pure-bloods. These types of wizards were becoming scarce as time went on and wizards started reproducing with muggles and half-bloods.
Sirius wasn't the only son to Orion and Walburga, he had a younger brother named Regulus. Regulus was killed after betraying Lord Voldemort in 1979. Regulus had found one of Voldemort's Horcruxes, and he was killed by one of the Inferi guarding the Horcrux after he retrieved it. Sirius did not know this was how his brother was killed and died thinking he was a chicken who got cold feet and tried to run. Sirius is quoted as saying this about Regulus to Harry:
"He was murdered by Voldemort. Or on Voldemort's orders, more likely, I doubt Regulus was ever important enough to be killed by Voldemort in person. From what I found out after he died, he got in so far, then panicked about what he was being asked to do and tried to back out. Well, you don't just hand in your resignation to Voldemort. It's a lifetime of service or death."
Though Sirius' parents believed in the purification of the wizarding race they were not Death Eaters. Regulus had made them beyond proud when he became a Death Eater. As you can see Sirius and Regulus were polar opposites. Sirius was a Gryffindor, Regulus was a Slytherin. Sirius didn't give into his parents' propaganda that anyone that wasn't a pure-blood was scum, while Regulus did. In the eyes of Orion and Walburga, Regulus was the perfect son, while Sirius was not. Sirius' beliefs eventually led him to being considered as a blood traitor and being burnt off the family tapestry.
Sirius' name was a traditional one in the Black family. Most of the past three generations of Blacks were named after stars, constellations, and galaxies. Most of the names occur quite often in the family tree, like Cygnus, Arcturus, and Regulus. However, there are only three known Sirius Blacks; one of the first people on the family tree was the brother of Phineas Nigellus Black (who died at the age of eight), the great grandfather of the Sirius we are discussing, and of course the Sirius we are talking about now. Is it a funny coincidence how the Blacks started with a Sirius and the family name ended with a Sirius. You can see the family tree of the Blacks above.
Time At Hogwarts
As you read above, Sirius did not hold the same values as his family. This was even more apparent when he was sorted into Gryffindor. The only Black in the line to be placed there. You can imagine he had quite the unhappy childhood with his different values. By the time he had become a teenager he hated most of his relatives; the two people on top of that list were his mother and his cousin Bellatrix. Sirius took great pride in being sorted into Gryffindor. He even went to the trouble of hanging Gryffindor banners all over his room at home, to show how different he was from his family.
You can imagine how horrible it must have been for Sirius to grow up in that kind of situation. His life at Hogwarts however, was the complete opposite. Like our Harry Potter, he greatly enjoyed living at Hogwarts. From the first time he met James Potter they instantly became best friends and inseparable. Later on they became friends with Remus and Peter. They discovered that Remus was a werewolf in their second year and to support him the three friends became illegal animagi. By doing so they were able to be around Remus during his transformations, keeping Remus' mind while he was the beast. In his animagus form Sirius took the shape of a huge black dog. His nickname derived from the padded feet a dog possesses.
By the age of sixteen Sirius had finally had enough of his family. Sirius ran away from home, taking refuge with James and his family. This infuriated his mother, leading her to blast his name off of the family tree. Not all family members agreed with how Walburga reacted. Her brother Alphard, Sirius' uncle, sympathized greatly with Sirius. When Alphard died, he left Sirius with a large inheritance. This caused Walburga to become livid and blast Alphard's name off of the family tree as well. This inheritance left Sirius financially independent for the rest of his life. It is this inheritance that allows Sirius to buy a new broom for Harry Potter years later.
During his time at Hogwarts, Sirius was immensely popular. His teachers respected him for his intelligence and girls adored him for his dark good looks. While teachers respected his intelligence they didn't agree with his behavior and many teachers thought of them as troublemakers or practical jokers. Hagrid had once compared Sirius and James to Fred and George Weasley. Not everyone liked Sirius though. From the very beginning James and Severus Snape developed a mutual hatred for one another. Sirius of course, sided with James.
Snape: "If you'd rather be brawny than brainy—"
Sirius: "Where're you hoping to go seeing as you're neither?"
— Sirius and Snape on the Hogwarts Express discussing Hogwart's Houses
This led to Snape developing an equal and life-long loathing towards Sirius. James and Sirius went out of their way to bully Snape, more then once their bullying had turned physical. Sirius admitted that he and James were "arrogant little berks" and considered himself an idiot during this time.
James: "How'd the exam go, Snivelly?"
Sirius: "I was watching him, his nose was touching the parchment. There'll be great grease marks all over it, they won't be able to read a word..."
— James and Sirius bully Severus Snape as teenagers
The hatred between Snape and Sirius didn't die down when they reached later stages in their careers at Hogwarts. Unfortunately, it got worse - a lot worse. Sirius had decided to play a horrible joke on Snape. Sirius informed Snape how to enter the tunnel under the Whomping Willow, this of course could had led to Snape's death. Unknown to Snape as he made his way to the Shrieking Shack, Remus was in there for one of his monthly transformations. When James found out about what Sirius had done, James was forced to rescue him. The resentment Snape had for Sirius after that never healed.
First Wizarding War
Sirius and James remained the best of friends, like brothers. Sirius attended James' wedding to Lily Evans as his best man. When James and Lily had their first born, Harry, Sirius was named as godfather. Sirius viewed the Potters' as his family. Sirius also gave Harry a toy broom on his first birthday.
When Sirius' life at Hogwarts was over he joined the fight against Lord Voldemort, eventually becoming a member of the Order of the Phoenix. In 1977, Sirius and James were involved in a motorcycle chase with two policemen. At the beginning the entire thing was fun, James and Sirius making jokes. However, things turned more serious when they were attacked by three men on broomsticks, believed to be Death Eaters. Sirius and James used their wands to levitate the police car, causing their attackers to crash into it.
During the Wizarding War, Sirius was surrounded by rumors, mistrust, and stress. This took a toll on him and by October 1981, he no longer fully trusted werewolf Remus Lupin. Sirius believed Remus was a spy and decided to exclude him from certain information; this decision would lead to the deaths of James and Lily Potter.
In 1981, the Potters became aware that Harry had become one of Lord Voldemort's specific targets. Albus Dumbledore urged the Potters to go into hiding using the Fidelius Charm. Dumbledore suggested himself as Secret-Keeper, however James was adamant that Sirius was to be their Secret-Keeper, knowing that Sirius would willingly die rather than reveal where they were. However, believing that Voldemort would instantly suspect him, Sirius suggested Peter instead. James agreed; they kept everyone in the dark about their plan, using Sirius as a decoy Secret-Keeper.
On Halloween night of the same year, Sirius went to check on Peter's hiding place. He found him missing. Sirius saw that there were no signs of a struggle and frantically sped to Godric's Hollow. He was too late though. When he arrived, he discovered the Potters' house destroyed, James and Lily dead inside. Baby Harry was still alive though. When Hagrid appeared at Godric's Hollow to rescue Harry on Dumbledore's orders, Sirius offered to take Harry himself. Hagrid told him that Dumbledore had already made plans for Harry to live with his Aunt and Uncle. Sirius accepted this and offered Hagrid his flying motorcycle, saying that he wouldn't need it. Sirius handed Harry back to Hagrid and took off.
After Sirius left Godric's Hollow, his sole mission was to track down Peter and kill him in vengeance. Peter was expecting this, when Sirius confronted him on a city street, Peter created a huge explosion and faked his own death. Peter left a severed finger behind as evidence, also killing twelve Muggles in the process. Moments later, Sirius was arrested by the Department of Magical Law Enforcement and was sentenced to Azkaban without a trial. His crimes were for the murder of Peter and the twelve Muggles, for giving the information about the Potters' whereabouts to Voldemort - leading to their deaths, and for being in service to Voldemort. Sirius would spend the next twelve years in solitary confinement in Azkaban.
Between Wizarding Wars
The twelve years in Azkaban did nothing for Sirius’ mental state. He was driven to the brink of madness. The only thing that was able to keep him sane was by focusing on his innocence. He later went on to explain that his innocence was more of an obsession than a happy thought, so it could not be detected by the Dementors, but was still able to give him comfort. His innocence wasn’t his only obsession though, he also obsessed over James and Lily’s deaths, as well as Peter’s betrayal.
In 1993, Sirius was able to escape Azkaban. He was the first known wizard to ever escape the place. Dementors have difficulty sensing an animal's emotion, which made this the ideal opportunity for Sirius. One day while Cornelius Fudge was in Azkaban for an inspection, Sirius had casually asked to borrow his Daily Prophet, to which Fudge handed it over. That issue of the Daily Prophet had the Weasley family on the front page, along with Ron's pet rat. Sirius instantly knew it was Peter in his animagus form, which he had seen so many times, because the rat was missing one of its fingers. Sirius was now filled with even more desire for revenge and to protect Harry. He hastily formed an escape plan. Sirius was very malnourished from his time in prison, so thin in fact he was able to slip through the bars of his cell in his dog form. It was easy enough to slip past the dementors as a dog. After that he swam across the North Sea. This journey nearly killed him, but with the thought of Peter being so close to Harry, he pushed himself on.
Sirius made his way to Little Whinging, where he caught his first glimpse of Harry as he was running away from his aunt and uncle's house. Harry was startled when he caught sight of the dog, but before Harry could investigate any further the Knight Bus showed up and Sirius was gone. At this time, the majority of the wizarding world still believed Sirius to be a murderous traitor that had now escaped from Azkaban to kill Harry and somehow bring Voldemort back to power. Of course, this couldn't have been further from the truth.
Once Sirius arrived at Hogwarts he needed a place to stay, one that didn't have a lot of student traffic. He decided that Hogsmeade would be the ideal spot. He would have a chance to eat scraps from the Three Broomsticks and could still stay in his animagus form. He was mistaken for the grim the few times he was sighted by students. There was only one person, well animal, that knew what Sirius truly was and that was Hermione Granger's cat Crookshanks. Not only did Crookshanks know what Sirius was, he knew that Scabbers was really Peter as well. Crookshanks actually tried to bring Peter to Sirius, but was unsuccessful as Ron Weasley interjected. Sirius eventually became so desperate that he made his way into the Shrieking Shack and through the tunnel to Hogwarts.
In June, while Sirius was watching the trio make their way across the grounds, he noticed Ron was carrying Scabbers. Sirius took the chance he had and grabbed Ron, in his dog form of course, dragging Ron and Scabbers through the tunnel under the Whomping Willow. Harry and Hermione followed the dog in order to save their friend. In the shack Sirius transformed back into himself and Harry attacked him. Harry was still under the impression that Sirius was responsible for killing his parents. Remus comes into the shack before Harry has a chance to do anything too drastic and disarms Harry. Together both Sirius and Remus explain to Harry what Scabbers really is. Now that Harry finally knew the truth, Remus and Sirius went in for the kill. Peter begged for his life.
Sirius: "What was there to be gained by fighting the most evil wizard that ever existed? Only innocent lives, Peter!"
Peter: "You don’t understand! He would have killed me, Sirius!"
Sirius: "THEN YOU SHOULD HAVE DIED! DIED RATHER THAN BETRAY YOUR FRIENDS, AS WE WOULD HAVE DONE FOR YOU!"
— Sirius confronting Peter in 1994
Peter would not die that night, as Harry stopped the two friends from murder. Harry believed it would be better for everyone if they spared Peter's life and turned him over to the dementors, therefore clearing Sirius of the crimes he was framed for. Unfortunately, this is not how the night ended. On the way out of the Shack, Remus transformed into a werewolf, allowing Peter to flee. In order to protect Harry, Ron and Hermione from the werewolf, Sirius transformed back into his animagus form. This fight weakened Sirius and when the dementors arrived to collect him, he wasn't able to protect himself. The dementors went in for the "kiss," almost succeeding until a Patronus of a stag appeared, sending them away. This Patronus was produced by Harry Potter.
After the Patronus saved his soul, Sirius was recaptured by Severus Snape and sentenced to the dementor's "kiss" once more. Sirius was once again rescued by Harry Potter with the help of Hermione Granger and her time-turner. Once back in time, Harry and Hermione were able to save the life of not only Sirius, but also Buckbeak the hippogriff. Saving Buckbeak was more than a favor to Hagrid, it allowed Sirius to fly to safety. Once Sirius was safely away he sent a letter to Harry explaining he was the one that sent him a Firebolt for Christmas, and he also signed a permission slip for Harry that allowed him to go into Hogsmeade, since Sirius was legally his guardian. As a thanks, Sirius said the owl that brought the letter to Harry was a gift for Ron. Sirius said that he owed Ron a pet; Ron's little sister Ginny named the owl, Pigwidgeon.
Second Wizarding War
The next year after his escape from Azkaban, Lord Voldemort was returned to his old physical form. Because of this Dumbledore, reinstated the Order of the Phoenix the year after. To his own frustration, there wasn't a lot Sirius could do to help, as he was still a wanted man. He was able to do one thing to help the Order though, he was able to give them a headquarters. Sirius donated his old family home to the cause. Since he was still on the run from the Ministry, he was forced to move back into the house that held so many terrible childhood memories. Sirius hated being locked up, especially in this house. He often felt useless, a fact that Severus Snape rubbed in whenever the two were in the same room.
Sirius kept in contact with Harry as much as he could from Grimmauld place, by writing him letters and talking through the Floo Network. Most of the time however, he was alone in the house with no one but the family House-Elf Kreacher and nothing to do. He began to let himself go, not shaving, wearing his pajamas the entire day, and drinking. Harry was beginning to worry about Sirius. Unfortunately, Lord Voldemort could sense his attachment towards Sirius and used it against him.
Lord Voldemort implanted a false vision into Harry's mind, making him think that Sirius had been captured and was being tortured to death. Harry was convinced Sirius was in trouble and did the only thing he thought he could do. He went to rescue him with the help of five of his classmates. Unfortunately, once they arrived they were ambushed by a group of Death Eaters. Harry now knew that the vision was fake and Sirius was still safely in Grimmauld place. When the Order was alerted by Severus Snape that they were in trouble, Sirius raced to help Harry with a group of Order members. As Sirius fought with his cousin, Bellatrix Lestrange, she shot a spell at him. The spell hit Sirius squarely in the chest. No, it wasn't the spell that killed him. He lost his balance when the spell made contact and fell backwards through a Veil. This Veil was located in the Death Chamber. He was dead as soon as he passed through it. After his death, the Ministry recognized that Sirius was indeed innocent and his name was cleared. In Sirius' will he left everything he owned to Harry Potter.
It took Harry years before he was ever able to come to terms with Sirius' death. Two years after his death as Harry is getting ready to face Lord Voldemort, Harry has in his possession the Resurrection Stone. He used this to bring back his parents, Remus Lupin and Sirius in their ghost forms. As Harry walked to what he thought was his death, he brought them with him.
Harry: "Does it hurt?"
Sirius: "Dying? Not at all. Quicker and easier than falling asleep."
— Sirius' spirit speaks to Harry through the Resurrection Stone
The stone eventually slips from Harry's hand and with that the ghosts of his loved ones vanished.