Severus Snape is also a half-blood (he gave himself the nickname "The Half-Blood Prince"), as his father Tobias Snape was a Muggle. Harry himself is a half-blood, since his pure-blood father, James, married a Muggle-born witch named Lily, and his maternal grandparents were Muggles.
How is Harry a half-blood if both parents are wizards?
By the 1990s, most of the magical population were half-bloods. The children of Harry and Ginny Potter were considered half-bloods because although Ginny was pure-blood, Harry's mother was Muggle-born.
It's revealed that the Half-Blood Prince was a nickname which Snape coined for himself whilst at Hogwarts. The title pays tribute to the wizard's blood status. Like Harry, Snape was a Half-Blood. His father, Tobias Snape, was a Muggle, whilst his mother, Eileen Prince, was a witch.
People of this mixed parentage are called half-bloods; magical people with any Muggle ancestry on the one side or the other are half-bloods as well. The most prominent Muggle-born in the Harry Potter series is Hermione Granger, who was born to Muggles of undisclosed names.
Luna Lovegood is a Pureblood witch, who was sorted into Gryffindor House during Harry Potter's second year at Hogwarts School of Witchcraft & Wizardry.
Snape was born to Eileen Prince, a witch, and Tobias Snape, a Muggle, making him a half-blood (hence the name, "Half-Blood Prince"). This is rare for a Death Eater, as remarked in the last book, though Voldemort himself also had a Muggle father.
In Harry Potter's third year at Hogwarts, his nasty, bullying Potions master, Severus Snape, tells him openly for the first time how much he hated Harry's dead father, James: 'He, too, was exceedingly arrogant… Strutting around the place with his friends and admirers… the resemblance between you is uncanny.
Lily Luna Potter (b. c. 2008) was an English half-blood witch, the youngest child and only daughter of Harry and Ginevra Potter (née Weasley). Lily had two older brothers, James Sirius and Albus Severus Potter.
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.
Draco Lucius Malfoy (b. 5 June 1980) was a British pure-blood wizard and the only son of Lucius and Narcissa Malfoy (née Black). The son of a Death Eater, Draco was raised to strongly believe in the importance of blood purity. He looked down on half-bloods and Muggle-borns.
Despite being a pure-blood, he didn't believe that he was superior to other witches, wizards and Muggles. He had a lot going for him and his well-placed morals were even more impressive if you think about the start that he had in life. Sirius came from a family of pure-blood fanatics.
Wizards and witches hid their world with Muggle-Repelling Charms, and if a Muggle witnessed a magical event or saw a magical creature such as a dragon, their memories were erased.
Pure-blood elitism. The most extreme of the pure-blood supremacists sought to purge the world of those they consider "impure". They often tolerated half-bloods out of necessity (though still disdained them), but Muggle-borns were persecuted and Muggles were viewed as nothing more than animals.
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.
Why did Snape hate Hermione? I think Snape was probably initially impressed with Hermione, but later frustrated with her, for a few reasons. Hermione was very book-smart and could come up with answers quickly, but didn't seem to be very good at improvising or trying to improve on existing Magic.
Malfoy was born in a pure blood family and had no doubt heard of the baby who defeated Voldemort, which would have intrigued him. Therefore he tried to befriend Harry, but came off as rude, which got him rejected. He then proceeded to bully Harry and his friends to avenge the rejection.
In his fifth year James saved Severus Snape from a near-fatal prank that Sirius Black played on him, which involved luring Snape to the Shrieking Shack where Remus Lupin was in his werewolf form. As such, Snape owed James a life debt, although they hated each other.
By Harry Potter and the Deathly Hallows, it's a stretch to call Draco a villain anymore. We just watched — or read — him struggle to reconcile his choices and morals in The Half-Blood Prince. He can no longer justify his actions, and is far more aware of the evil he was born and raised into.
The movies follow the books closely enough that they aren't really separate universes, except for the fourth movie. There isn't any truly compelling evidence that Snape is Harry's father, because all the points you raise are explained. Snape hated Harry because Harry reminded him of the man who "stole" Lily.
In the heat of the moment, Snape lost control and called Lily the forbidden word. He called her a mud-blood by accident because he was frustrated that lily did not like his closest friends. He did not mean it.
The Potters' generational wealth is traced back to their ancestor, Linfred of Stinchcombe, who amassed a great fortune through his medicinal services and inventions of healing potions.
No, they are not. Luna's parents are clearly stated to be Xenophilius and Pandora Lovegood, while Draco's parents are clearly stated to be Lucius and Narcissa Black Malfoy.
