Behind the scenes When Sirius gives Harry the mirror in a badly wrapped package, Harry vows to himself he will never use it, not wanting to lure Sirius from his place of safety.
What if Harry had used the mirror to talk to Sirius?
Harry would've tried the mirror, called Sirius's name multiple times and seeing no response would've concluded that he was indeed at the ministry. He might not even consider Umbridge's fireplace in that case. Most of the events would happen the same way since then and Sirius would have still died, just like he did.
It makes sense that Rowling wanted Harry to forget about the mirror because it would serve as a tragic learning opportunity for Harry, and would create an even sadder layer to Sirius' death.
What mirror communication device was gifted to Harry by Sirius?
A pair of mirrors that served as communication devices between two people, one with each half. James Potter and Sirius Black had enjoyed using a pair of mirrors to speak to each other in detention at Hogwarts. Years later, Sirius gave Harry the half originally owned by James.
What If Sirius TOLD HARRY How To Use The Mirrors | Harry Potter Film Theory
Why didn't Harry contact Sirius?
When Sirius gives Harry the mirror in a badly wrapped package, Harry vows to himself he will never use it, not wanting to lure Sirius from his place of safety.
Then there was Sirius' relationship with Harry. He was the father figure that Harry so desperately needed. For one of the first times in his life, Harry experienced what it was like to be unconditionally loved and that family doesn't necessarily mean your blood relatives.
Lucius reveals that Harry only saw a dream of Sirius being tortured; it was a method to lure Harry into the Death Eaters' grasp, not an actual situation. Lucius attempts to persuade Harry to give him the prophecy, telling him it will reveal why Voldemort couldn't kill Harry when he was an infant.
The mirror was a gift from Sirius given to Harry in “Order of the Phoenix.” The mirror is part of a set that allows people to communicate with each other. After Sirius' death, Harry put it in his school trunk and forgot about it until Deathly Hallows.
At the height of the Battle of the Department of Mysteries, most of the fighting was set in the Death Chamber; and Bellatrix Lestrange hit her cousin Sirius Black squarely on the chest with a spell, throwing him off balance and sending him through the Veil to his death.
To defend her students, McGonagall casts a series of spells Snape's way, but he manages to evade all of them before flying away. But what McGonagall doesn't know is that Snape is actually a double agent working for Dumbledore, so he has no intention of harming her.
Honestly, Hermione knew Dobby was a lost case... nothing could have revived Dobby after the attack or she would have definitely helped Harry with Dobby considering she was the girl who started S.P.E.W(Society for the Elfish welfare) and fought for elf rights. There was nothing to be done at that point.
Aberforth was devastated by the death of the younger sister he and his mother spent years caring for and furiously blamed Albus for Ariana's death, going as far as to physically assault his brother at their sister's funeral and actually breaking Albus's nose, shouting that Ariana's death was his fault.
What would have happened if Harry lived with Sirius?
Therefore, if Harry had gone to live with Sirius while he was still underage, he would not be safe from Voldemort. The miserable years he spent with the Dursleys would have been for nothing and he would be without the protective shield of his mother's blood.
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.
His dad gave it to him. To elaborate on Icecreamdif's answer, he inherited it as a family heirloom dating back to Hardwin Potter, who married Iolanthe Peverell, granddaughter of the Cloak's original owner Ignotus. It was passed down to the eldest male of each new generation of Potters since then.
The books explain it well, mutilating one's soul is something that debilitates the body and soul of those who create Horcruxs, making too many is dangerous which is why Voldemort didn't make others, which is why over time he becomes less human but more similar to a snake.
Sirius is recognized for his unwavering loyalty and love for his friends and Harry. He loves Harry, and his affection is generous. He was devoted to James, Lily, Remus, Harry, Ron, Hermione, Gryffindor, and the Order.
Sirius wasn't mean to Harry. He was just depressed that even the Headquarter of the Order of the Phoenix was in his own house, he couldn't contribute to it. Sirius was an extremely energetic man. Rebellion was in his blood.
In the Order of the Phoenix novel, JK Rowling introduced another magical object to the canon: a two-way mirror that allows communication between its owners. The book had Sirius give Harry the mirror after Christmas break and urged him to use it if Snape was giving him a hard time.
The prolonged misery of being exposed to dementors kept the prisoners locked within their own minds, so Sirius lost the ability to transform. However, Sirius explained that the knowledge of his innocence kept him sane in a way most of Azkaban's prisoners were not.
He'd loved her, he really had. He'd also loved Sirius. He hadn't known that Sirius was in love with him too, not until his wedding day. As much as everything in James had ached to say 'I love you too, let's leave together', he hadn't been able to do that to Lily.
As the last remaining descendent of the House of Black, Sirius inherits centuries of gold, heirlooms, and unwanted Pure-Blood prejudice. In addition to his ancestral home of 12 Grimmauld Place, he possesses all that was left to him by his Uncle Alphard.
