The Malfoys are related to the Black family through Narcissa (a first cousin of Sirius Black, Harry's godfather), which makes Draco a nephew of both Bellatrix Lestrange and Andromeda Tonks. Draco is also Nymphadora Tonks' first cousin through their mothers.
Draco's mother is Narcissa Black, which makes Draco Sirius' second cousin. So once again we find this family tree getting just a bit more complex and twisted. Thankfully this is a connection that Harry failed to notice, at least to our knowledge.
This is further supported by the fact that the entire House of Black is seen on the tree, making it very unlikely that another option is possible. Meanwhile, Molly's parents are unknown. We do know, again from Sirius, that Molly is his cousin by marriage.
Bellatrix is a member of the Black Family and is the cousin of Sirius Black. Bellatrix is the daughter of Cygnus and Druella Black and sister to Andromeda (mother of Nymphadora Tonks) and Narcissa (mother of Draco Malfoy).
Draco is related to Sirius through Bellatrix Lestrange as she is Sirius's cousin. Since Sirius is Harry's godfather, they are related that way, but not by blood.
How EVERY Harry Potter Character is RELATED (All Family Trees Explained)
How is Draco related to Bellatrix?
A member of the house of Black, one of the oldest wizarding families, Bellatrix was also Draco Malfoy's aunt. Renowned for her cruelty and sadistic nature, many of the acts of torture and violence against Voldemort's enemies were carried out by Bellatrix Lestrange.
Sirius had a younger brother, Regulus Arcturus Black, and three older cousins: Bellatrix Lestrange, Andromeda Tonks (his favourite cousin and mother of Nymphadora Tonks), and Narcissa Malfoy (mother of Draco Malfoy).
In Harry Potter and the Cursed Child, it is revealed that Bellatrix gave birth to Voldemort's daughter Delphi in Malfoy Manor before the Battle of Hogwarts.
Delphini was born in secret at Malfoy Manor in early March 1998 as the result of a liaison between Bellatrix Lestrange and Lord Voldemort. On 2 May 1998, both of her biological parents were killed in the Battle of Hogwarts.
As the daughter of Sirius Black, Cassiopeia is the rightful blood heir to the House, despite being female. As a pureblood, Cassiopeia is related to many wizarding families, such as the Malfoys, Tonks, Weasleys, Prewetts, Longbottoms, Crabbes, Flints, Crouchs, and others.
Black did not have a wife or children. As the portrait of Phineas Nigellus, Black's deceased great-great-grandfather, stated, the direct line of the ancient Black family ended with Sirius' death. Had Regulus Black lived, he would have been the heir of the Black home; however, he predeceased Sirius.
When Lucius turns on Voldemort due to the reveal of his Horcruxes, Narcissa divorces him, taking 75% of Malfoy's wealth with her. Even her relationship with Draco is different, with POS-Narcissa only viewing Draco as a tool to further her own agenda.
J.K. Rowling says Draco doesn't have a patronus because he never learned the spell but I think it's because he doesn't have any powerful happy memories to use. He has tons of happy memories... He had an amazing childhood. However, she also said Snape was the only Death Eater who could produce a Patronus.
Sirius' family tree includes some nefarious characters. Bellatrix Lestrange, Narcissa Malfoy, and Sirius Black are all descendants of Pollux Black, making them first cousins. Note: For space's sake, this tree doesn't include Andromeda Tonks or her husband and daughter.
Before her death, Bellatrix secretly gave birth to an illegitimate daughter named Delphini, whom she conceived with her beloved master, Lord Voldemort. Delphini was conceived sometime after the Battle of the Department of Mysteries in 1996 and before the Skirmish at Malfoy Manor in 1998.
She was raised by Euphemia Rowle then Rodolphus Lestrange. It would not be very surprising if they told her everything about Voldemort, his greatness, his power, his ambitions… since he was their master.
Despite Bellatrix's obvious feelings for Voldemort, there was no real love connection between them, as Voldemort was incapable of love due to his soul being fragmented through Horcruxes.
Luna married fellow naturalist Rolf Scamander, grandson of Fantastic Beasts and Where to Find Them author Newt Scamander, considerably later in life than Harry, Ron, Hermione, and Ginny, who all married and started families in their early-to-mid twenties.
Harry Potter had a few love interests during his time at Hogwarts. Though he eventually settled down with Ginny Weasley, he also had a thing for Cho Chang in his earlier school years. Then, of course, there's his secret love for Draco Malfoy… Wait, what?
Rowling revealed more information about Neville when she stated that he married Hannah Abbott, a Hufflepuff classmate, who became the landlady of the Leaky Cauldron. The couple live over the pub, a fact that Rowling thought people would find "particularly cool".
Remus fought at the Battle of Hogwarts on 2 May 1998, during which his wife was murdered by Bellatrix Lestrange. Remus was also murdered by Death Eater Antonin Dolohov, during the first half of the same battle. His death was possibly avenged by Filius Flitwick.
Although Harry Potter doesn't have any siblings JK Rowling revealed in an interview that Lily was in fact pregnant with second child when she was killed by dark lord. She had even managed to convince James to make Severus godfather of the second child.
All three members are related or blood related to the Weasleys, as Ron is a Weasley, Hermione married Ron making her a Weasley by marriage, and Harry married into the Weasley family through Ginny making him an in-law to the Weasley family, as well. The three are also related in some way to the Black family.
