Vincent Crabbe – Slytherin student in Harry's year, son of Death Eater, Slytherin Quidditch team Beater, member of the Inquisitorial Squad, friend of Draco Malfoy.
Colin Creevey – Muggle-born Gryffindor student one year below Harry, brother of Dennis Creevey, member of Dumbledore's Army, killed during the Battle of Hogwarts, after sneaking away from the younger evacuated students in the seventh book
Dennis Creevey – Muggle-born Gryffindor student three years below Harry, brother of Colin Creevey, member of Dumbledore's Army
Dirk Cresswell – Muggle-born Head of the Goblin Liaison Office, went on the run in Deathly Hallows with fellow muggle-born Ted Tonks, Dean Thomas and goblins Gornuk and Griphook.
Albus Dumbledore – Hogwarts Headmaster in Harry Potter's time, Transfiguration professor in Tom Riddle's time, founder of the Order of the Phoenix.
Ariana Dumbledore – Sister of Aberforth and Albus Dumbledore, magically unstable after an assault by muggle boys when she was little, killed accidentally in childhood by either Albus, Aberforth or Gellert Grindelwald.
Dudley Dursley – Muggle son of Vernon Dursley and Petunia Evans, first cousin of Harry Potter
Marvolo Gaunt – Pure-blood father of Merope and Morfin Gaunt, grandfather of Tom Marvolo Riddle.
Merope Gaunt – Daughter of Marvolo Gaunt, sister of Morfin Gaunt, wife of Tom Riddle Sr, mother of Tom Marvolo Riddle/Lord Voldemort, died after childbirth, named for Merope, one of the Pleiades, who married a mortal
Morfin Gaunt – Son of Marvolo Gaunt, sister of Merope Gaunt, uncle of Tom Marvolo Riddle, framed by his nephew for Muggle killings.
Bellatrix Lestrange (née Black) – Death Eater, sister of Narcissa Malfoy and Andromeda Tonks, cousin of Sirius and Regulus Black, she tortured Frank and Alice Longbottom into insanity with husband Rodolphus.
Rodolphus Lestrange – Death Eater, brother of Rabastan Lestrange, husband of Bellatrix Lestrange, uncle of Nymphadora Lupin (née Tonks) and Draco Malfoy, tortured Frank and Alice Longbottom into insanity with wife Bellatrix
Gilderoy Lockhart – Fraudulent celebrity author, Defence Against the Dark Arts teacher.
Alice Longbottom – Wife of Frank Longbottom, mother of Neville Longbottom, member of the original Order of the Phoenix, Auror, tortured into insanity by Bellatrix Lestrange along with her husband
Theodore Nott - Slytherin student in the same year as Harry Potter. Nott is one of the few students who can see Thestrals, suggesting that he has witnessed a death at some point. His father is a Death Eater, and described as an elderly widower.
Pansy Parkinson – Slytherin student in Harry's year, school prefect, member of the Inquisitorial Squad, Draco Malfoy's girlfriend for some time.
Padma Patil – Ravenclaw student in Harry's year, identical twin sister of Gryffindor Parvati Patil, member of Dumbledore's Army.
Parvati Patil – Gryffindor student in Harry's year, identical twin sister of Ravenclaw Padma Patil, member of Dumbledore's Army.
Peter Pettigrew – Former school friend of James Potter, Sirius Black and Remus Lupin. Betrays James and Lily Potter. Death Eater, an unregistered animagus, Pettigrew is first introduced as a rat known as Scabbers.
Antioch Peverell – Original owner of The Elder Wand in The Tale of the Three Brothers.
Cadmus Peverell – Original owner of The Resurrection Stone in The Tale of the Three Brothers
Ignotus Peverell – Original owner of The Invisibility Cloak in The Tale of the Three Brothers.
Pius Thicknesse – Minister for Magic while under the Imperius Curse, later replaced by Kingsley Shacklebolt.
Dean Thomas – Gryffindor student in Harry's year, member of Dumbledore's Army, briefly Ginny Weasley's boyfriend, Gryffindor Quidditch Chaser.
Andromeda Tonks – Sister of Bellatrix Lestrange and Narcissa Malfoy, disowned by her family for marrying Muggle-born Ted Tonks, mother of Nymphadora Lupin (née Tonks), grandmother of Teddy Remus Lupin,
Nymphadora Tonks – Daughter of Ted Tonks and Andromeda Black, disowned by the Black family for being half-blood, Auror, metamorphmagus, wife of Remus Lupin, mother of Teddy Remus Lupin.
Ted Tonks – Muggle-born husband of Andromeda Black, father of Nymphadora Tonks.
Sybill Patricia Trelawney – Hogwarts Divination professor, predicted the prophecy that prompted Lord Voldemort to go after the Potters
Dolores Jane Umbridge – Senior Undersecretary to the Minister for Magic, Defence Against the Dark Arts professor, Hogwarts High Inquisitor, Headmistress of Hogwarts, who enthusiastically joins in the persecution of half-bloods under Voldermort.
Arthur Weasley – Muggle-obsessed Ministry of Magic employee at the Ministry for Magic. Husband of Molly Weasley, father of Bill, Charlie, Percy, Fred, George, Ron, and Ginny Weasley, member of the Order of the Phoenix
Bill Weasley – Oldest son of Arthur and Molly Weasley, Gringotts employee.
Charlie Weasley – Second son of Arthur and Molly Weasley, and member of the Order of the Phoenix, works with dragons in Romania.
Fred Weasley – Son of Arthur and Molly Weasley and identical twin brother of George Weasley, member of Dumbledore's Army, Gryffindor Quidditch Beater, co-owner of Weasleys' Wizard Wheezes.
George Weasley – Son of Arthur and Molly Weasley and identical twin brother of Fred Weasley, member of Dumbledore's Army, Gryffindor Quidditch Beater, co-owner of Weasleys' Wizard Wheezes
Ginny Weasley – Only daughter and youngest child of Arthur and Molly Weasley, Gryffindor student one year under Harry, Gryffindor Quidditch Seeker and Chaser, member of Dumbledore's Army.
Molly Weasley (née Prewett) – Wife of Arthur Weasley, mother of Bill, Charlie, Percy, Fred, George, Ron and Ginny Weasley, member of the Order of the Phoenix.
Percy Weasley – Third son of Arthur and Molly Weasley, Gryffindor prefect and Head Boy then Ministry of Magic employee, long estranged from his family before joining them against the Death Eaters in Deathly Hallows,
Ron Weasley – Harry's close friend, youngest Son of Arthur and Molly Weasley, Gryffindor Quidditch Keeper, school prefect, member of Dumbledore's Army.
Oliver Wood – Hogwarts student, Gryffindor Quidditch Keeper and captain.
Algie - Great-uncle of Neville Longbottom who tried to "startle" the magic out of him by endangering Neville's life repeatedly. Gave Neville his toad Trevor as a gift when Neville finally showed his first known bit of accidental magic.
Aragog – Acromantula belonging to Rubeus Hagrid, lives in the Forbidden Forest, dies in Half-Blood Prince.
Arnold - Ginny's pygmy puff she got before her fifth year, one of many bred by her twin brothers for sale in their shop.
Dobby– House-elf originally belonging to the Malfoy family, accidentally set free by Lucius Malfoy due to Harry's intervention in Chamber of Secrets. Killed by Bellatrix Lestrange while saving Harry Potter's life.
Kreacher – House-elf belonging to the Black family, and later Harry Potter. Though at first preferring to serve the pureblood line (including Regulus Black, Narcissa Malfoy, Bellatrix Lestrange, and Draco Malfoy), he eventually likes serving under Harry as he treats him better, giving him Regulus' locket as a gift.
Winky - A female house elf who originally belonged to Bartemius Crouch Sr., but was sacked by him when evidence emerged that she had used magic at The Quidditch World Cup. Currently working at Hogwarts School of Witchcraft and Wizardry