In the Harry Potter series, there are different blood types or class types. There are the purebloods, mud bloods, halfbloods and the Squibs. The purebloods come from families of only wizards for generations. The mud bloods have parents that are Muggle born or non-magic. The halfbloods have one wizard parent and one muggle parent or one muggle born parent. The most well known pureblood families are the Blacks, the Lestrange’s, the Longbottom’s, the Malfoy’s, the Ollivander’s, the Parkinson’s, the Peverell’s, the Prewett’s and the Weasley’s. The known Mudbloods in the Harry Potter series are Hermione Granger, Lily Evans, Colin Creevey and more. The known halfbloods ( from wizard parent and muggle parent or muggle born parent) are Remus Lupin, Nymphadora Tonks and Seamus Finnigan.
In Harry Potter and the Chamber of Secrets, Hermione Granger gets called a Mudblood, a derogatory term, by Draco Malfoy.
Hermione tells Harry and Ron “it means dirty blood” in the movie when they’re all in Hagrid’s hut.
Salazaar Slytherin, one of the four founders, thought only those with pure blood should be able to learn magic at Hogwarts School of Witchcraft and Wizardry. He thought “students of Muggle parentage were unworthy”.
Even though the Weasleys are considered pure blood, the Blacks and Malfoys still look down on them because of marrying Muggles or Muggle born wizards. In the Harry Potter and the Chamber of Secrets movie, Lucius Malfoy, Draco’s father recognizes the Weasley kids by their red hair and hand-me-downs.
There’s another example of this in the Harry Potter and the Order of the Phoenix movie. Sirius Black shows Harry the Black family tree and mentions how some people got marked out. The people got marked out of the family tree because they married Muggles or half-blood wizards.
Andromeda Black, Narcissa and Bellatrix’s sister, married Ted Tonks who was a Muggle-born wizard. Andromeda Black ended up getting marked off of the Black family tree.
Mrs. Figg, who is a Squib, was watching over Harry for Dumbledore and was part of the hearing in Harry Potter and the Order of the Phoenix.
In the Wizarding world, there are also magical creatures that aren’t treated as well as they should be. Dobby, a house elf, is treated poorly by the Malfoy family and like a servant not as an equal. Dobby, in the Harry Potter and the Chamber of Secrets novel, he is bound to serve them unless someone in the Malfoy family sets him free. It takes Harry Potter tricking Lucius Malfoy into giving Dobby socks that the house elf is now free.
In Harry Potter and the Goblet of Fire, Hermione Granger ends up creating Spew which is the Society for the Promotion of Elfish Welfare. She tells Harry and Ron “Elf enslavement goes back centuries”. She basically recruits Harry and Ron to be the other members with her.
It seems that some of the most powerful characters in the Harry Potter universe are either half blood or Muggle born. Hermione Granger was called the brightest witch of her age and Lily Evans was talented in her time at Hogwarts too.