Sirius Black Sirius Black is a Minifigure from the Harry Potter theme . His minifigure appears in 4756 Shrieking Shack and 4753 Sirius Black ' s Escape . Sirius also appears in Animagus form in 4755 Knight Bus , as a face in the fireplace in 5378 Hogwarts Castle and 4842 Hogwarts Castle , and on a wanted poster in 10217 Diagon Alley . A completely redesigned version of Sirius appears in . Background . Sirius Black belonged to a family who believed in pure blood supremacy , although he greatly disagreed with their beliefs . His childhood was unhappy , which led him to resent most of his family . When he attended Hogwarts he was sorted into Gryffindor , defying his family ' s tradition of Slytherin . He befriended James Potter , Remus Lupin , and Peter Pettigrew . He and James were known as the troublemakers at Hogwarts . When he discovered that Lupin was a werewolf , he along with his friends , spent years trying to become Animagi , so they could comfort Lupin during his transformations . During his fifth year he succeeded , becoming an animagus whose form was a large black dog . So they could talk about there adventures without people knowing , he was given the nickname Padfoot . After they left Hogwarts , he joined the Order of the Phoenix during the First Wizarding War . During this time James named Sirius the Godfather of , James ' s son . After the death of James and Lily Potter , he realized that they had been betrayed by Peter Pettigrew . He went searching for Peter to bring him to justice . But Peter killed off twelve muggles , cut off his finger to give the impression he was dead , and transformed into his animagus form of a rat , and escaped , leaving Sirius to take the blame . He was framed of murdering twelve muggles and Peter Pettigrew by Barty Crouch Senior and spent twelve years in Azkaban , the wizard prison . Sirius was able to survive those twelve years by reminding himself that he was innocent , and although it wasn ' t a happy thought , it kept him sane . While in prison , he gained possession of a newspaper , in which he discovered that Peter had been hiding as a rat with the Weasley family . Determined to bring Peter to justice , he escaped by transforming into a dog and slipping through the bars of his cell . Sirius tracked down Peter to Hogwarts . Sirius , along with Remus Lupin , tracked Pettigrew to the Shrieking Shack . After capturing him , the truth was revealed , and Harry and Co . became friends with Sirius . Unfortunately , before they could bring Peter to justice , Lupin transformed into a werewolf under the light of the full moon , creating enough of a distraction for Peter to transform into a rat and escape . Without proof of his innocence , Sirius was taken into custody and was sentenced to the " Dementor ' s Kiss " . With the use of a Time Turner , Harry and Hermione Granger were able to free Sirius , who escaped on Buckbeak the Hippogriff . Sirius , being the last heir of the Black family , took ownership of his old house at 12 Grimamauld Place , despite despising the place . At the start of the Second Wizarding War , 12 Grimmauld Place was used as the Headquarters of the Order of the Phoenix . Still on the run , Sirius was forced to stay in the house at all times . Being an energetic man , he hated being cooped up . His old House Elf , Kreacher , greatly disliked him , preferring his cousins , the Malfoy ' s . Kreacher betrayed Sirius by tricking Harry into believing that Sirius had been captured by Lord Voldemort , and was being held in the Department of Mysteries . After hearing that Harry had run off to the Ministry to save him , Sirius left his house with other members of the Order to save Harry . He was killed in the Battle of the Department of Mysteries by his cousin , Bellatrix Lestrange , when she used a curse and Sirius fell into the veil in the Death Chamber , which was a passage to the afterlife .