Inbreeding was a common practice for elite pure-blood wizarding families wishing to uphold the tradition of marrying only wizards of respected ancestry. It was noted that wizarding families became more diverse as time passed, as wizards began to marry half-bloods, Muggle-borns, and Muggles.
Because the only way for a family to retain their pure-blood status is to marry other pure-bloods, all pure-blood families were related to one another by the 1990s. Because of inbreeding among pure-bloods and some marrying Muggles and Muggle-borns, the number of families claiming to be pure-blood is declining.
Is everyone in Harry Potter related? Everyone, no. Most of the “pure-blood” or mixed-blood witches and wizards are, to varying degrees, related(either by blood, by marriage, or both) because of a tradition of intermarrying between pure-blood families.
Tom Riddle was left empty and hollow owing to both his heritage of inbreeding and lack of loving parents. When he was 16 years old he ventured to Little Hangleton and began investigating his parents' lives. He met his uncle Morfin Gaunt, and through him learned about Tom Sr.'s abandonment.
How EVERY Harry Potter Character is RELATED (All Family Trees Explained)
Is there inbreeding in Harry Potter?
Inbreeding was a common practice for elite pure-blood wizarding families wishing to uphold the tradition of marrying only wizards of respected ancestry. It was noted that wizarding families became more diverse as time passed, as wizards began to marry half-bloods, Muggle-borns, and Muggles.
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.
The Malfoys for example do not engage in inbreeding and sometimes even marry half-bloods. The Malfoys are not prejudiced against half-bloods. They're more the glass is half- full kind of people. In COS, Draco says that Harry has no wizard feeling because he hung out with a “mudblood”.
Lovegood was played by Rhys Ifans in Harry Potter and the Deathly Hallows. HIDDEN PAST: He is Lucius Malfoy's disowned brother. When he got married he took his wife's (Pandora Lovegood) surname. This act was further proof to his biological family that he was a blood traitor.
The pure-blood wizards and witches featured in the Harry Potter books are almost all supremacists, while there are some of them who do not advocate ancestral superiority; the Potters, Weasleys, and Longbottoms are old pure-blood families, but no known members of these families are sympathetic to supremacist aims.
Neville is a pure-blood wizard born to Frank and Alice Longbottom, who were prominent Aurors and also members of the Order of the Phoenix during the first war against Lord Voldemort.
The Granger family is very similar to the Evans family. Originally a muggle family, until a female member (Hermione and Lily Evans) became a muggle-born witch. The witch married a pure-blood man, (Ron Weasley and James Potter I) and have children, one of them a son (Rose and Hugo Weasley, Harry Potter).
Luna Lovegood is a Pureblood witch, who was sorted into Gryffindor House during Harry Potter's second year at Hogwarts School of Witchcraft & Wizardry.
It has nothing to do with genes and is just a construct of wizarding society. So the magical child of two muggle-born would be half-blood and a non-magical chld of two muggle-born a squib.
An interesting fact of note is that despite the ideals that pure-bloods are inherently more powerful wizards, some of the most powerful or particularly adept wizards and witches in the series are in fact either half-blood (such as Lord Voldemort, Albus Dumbledore, Minerva McGonagall, Severus Snape and Harry Potter) or ...
Cedrella and Septimus went on to have three children together, one of whom was Arthur Weasley – Ron's father. This means that Draco and Ron are distantly related, making Draco's bigoted pure-blooded ideology even more ironic.
Malfoy is the disowned older brother of Lord Lucius Malfoy. When he was young, he fell in love with and married Pandora Lovegood, who was a blood traitor. As such, his father disowned him and cast him out of the family. He took his wife's name and had one daughter with her: Luna Lovegood.
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…
In the play "Harry Potter and the Cursed Child," which has become part of "Harry Potter" canon, it was revealed that Bellatrix conceived a child with none other than Lord Voldemort.
Lord Voldemort had no wife he and Bellatrix just made a baby together. Voldemort couldn't love anyone. But the girl mother (In cursed child) is Bellatrix Leatrange.
She placed Cedric's father Amos Diggory under a powerful Confundus Charm and made him think that she was his niece, despite neither Amos nor his wife having any siblings. When Amos was put into a nursing home for elderly Witches and Wizards, Delphi accompanied him and acted as his caretaker.
