Draco Malfoy's mother Narcissa was cold, cunning and devoted to the Dark Lord. But she was also a mother, which meant she was willing to risk everything to make sure her son was safe. When Harry survived Voldemort's Killing Curse for the second time, Narcissa pretended he was dead so she could get to Draco.
Why did Narcissa Malfoy lie to Voldemort and say Harry Potter was dead when she knew he wasn't? Because she knew that letting Voldemort think Harry was dead and marching triumphantly into Hogwarts was the only shot she had at finding her son. And at that point, that is the only thing that matters to her.
Narcissa knew that the only way she would be permitted to enter Hogwarts, and find her son, was as part of the conquering army. She no longer cared whether Voldemort won. She didn't only want information about Draco, she wanted to get to him.
Draco had several reasons for lying to Bellatrix, including the fact that he was never a bad person. Moreover, he no longer found working for the Dark Lord appealing and hated how Voldemort treated his family. He did not intend to harm anyone and believed Harry was the only person capable of defeating Voldemort.
J. K. Rowling stated that Narcissa Malfoy was not a Death Eater, but merely agreed with the philosophy of blood purity. Why she never became a Death Eater is unknown, but it is most likely this was because of her overwhelming love, loyalty and commitment to her family above anything else.
Narcissa Malfoy's Very Dangerous Lie
But she was also a mother, which meant she was willing to risk everything to make sure her son was safe. When Harry survived Voldemort's Killing Curse for the second time, Narcissa pretended he was dead so she could get to Draco.
When Voldemort asked her to check if Harry was dead and she realised he was, in fact, still breathing, Narcissa seized her opportunity. Harry revealed that Draco was still very much alive, and she lied to her master in order to get closer to him.
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.
Cruciatus Curse ('Crucio')
Harry tried to use this spell himself. The first time was against Bellatrix after she had killed Sirius.
Harry Potter and the Deathly Hallows
In this book, Rowling reveals that Bellatrix is the guardian of Helga Hufflepuff's cup (though she is unaware that it is a Horcrux), which Voldemort has entrusted the Lestranges to keep in their Gringotts vault.
Despite being a valued Death Eater in the days before Voldemort fell following his attack on baby Harry, Lucius stumbled out of favor with the Dark Lord when he squandered Riddle's diary (secretly a horcrux) in Chamber of Secrets and failed to obtain the prophecy in Order of the Phoenix.
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.
Although Narcissa's motivation was to protect her family rather than go against Voldemort, the courage it took to lie to him can't be underestimated. The untruth she told him probably saved Harry's life – and sealed Voldemort's fate.
Malfoy hated all the attention Harry recieved . Malfoy thought Harry was a dark wizard, he tried to befriend Harry but he refused because of the way Malfoy treated Ron whom he already made friends with. That's why Malfoy hate Harry for turning him down.
Voldemort intentionally made six Horcruxes, but when he used Avada Kedavra on Harry, he unintentionally created a seventh Horcrux. Instead of dying, Lily's love for Harry created a counter 'curse' known as Sacrificial Protection and saved Harry.
This nuance was lost on Lord Voldemort, who wrongly assumed Severus Snape held the Elder Wand because he was Dumbledore's killer, when in reality Draco had disarmed Dumbledore before Snape arrived on the scene, making Malfoy the wand's true new owner.
In Deathly Hallows, Hermione faced a real test of her physical and psychological stamina. After being on the run from a bunch of Snatchers, the gang were taken to Malfoy Manor, where Bellatrix proceeded to torture Hermione using the Cruciatus Curse.
None of the good guys dare use the Killing Curse throughout the events of the movies and books, no matter how high the stakes and how difficult things are. But Ron Weasley is the exception, giving it a go in the Deathly Hallows: Part 2 movie when himself and Hermione look destined to die via Nagini.
His reaction to Bella's death was akin to his reaction at the loss of the Cup, which was when he realised that his own immortality was jeopardised amidst war and his own death could have been near.
Voldemort is a master manipulator. By humiliating Bellatrix as he does, he punishes her for her part in the failure at the Ministry of Magic — including her failure to finish off Tonks — and rouses her to try harder to murder members of her family.
He endured horrible things right from his unpleasant childhood, the death of his best friends to spending twelve years in Azkaban. His tragedy however didn't stop at his framing and imprisonment. Sirius met an undeserving death at the hands of Bellatrix Lestrange during the Battle of the Department of Mysteries.
“Is Draco alive? Is he in the castle?” The whisper was barely audible; her lips were an inch from his ear, her head bent so low that her long hair shielded his face from the onlookers.
Harry. So, the line Narcissa actually said was "Is he alive, Draco?" (As in is Draco still alive? In oppose to "Is he alive Draco?") Harry had just saved Draco, so he nodded. Narcissa pronounced him dead so Harry could reawaken afterwards and kill Voldemort.
Draco was torn between loyalty to his family, fear of Voldemort and worry for his former classmates.