Important Characters of Harry Potter (spoilers)

Harry James Potter
(later became head of the Auror office)

House: Gryffindor
Talent: Defense against the dark arts
Seeker of the Gryffindor Quidditch team

Wand: Holly, 11", phoenix feather and Elder, 15", Thestral hair (temporarily)
Patronus: Stag

Harry is the master of the Deathly Hallows.

Significant other: Ginny Weasley
Son of James & Lily Potter (deceased, members of Order of the Phoenix)

Other facts: When faced with a boggart, it takes the shape of a dementor.

Hermione Granger (later Weasley)
(later works at the Department of Magical Law Enforcement)

House: Gryffindor
Talent: Charms and Nonverbal magic

Hermione was the best student of her year.

Wand: Vine, 10¾", dragon heartstring
Patronus: Otter

Significant other: Ron Weasley
Hermione's parents are muggles.

Other facts: When faced with a boggart, it shows failure.

Ronald Bilius "Ron" Weasley
(later became an Auror)

House: Gryffindor
Talent: Tactics, such as Wizard's Chezz
Keeper of the Gryffindor Quidditch team.

Wand: Chestnut, 9¼", Dragon heartstring
Patronus: Jack Russell terrier

Significant other: Hermione Granger
Son of Arthur & Molly Weasley (members of Order of the Phoenix)

Other facts: When faced with a boggart, it takes the shape of an Acromantula.

Ginevra Molly "Ginny" Weasley (later Potter)
(later became a Quidditch player for Holyhead Harpies and Senior Quidditch reporter for the Daily Prophet)

House: Gryffindor
Talent: Bat-bogey hex
Chaser of the Gryffindor Quidditch team.

Patronus: Horse

Significant other: Harry Potter
Daughter of Arthur & Molly Weasley (members of Order of the Phoenix)

Neville Longbottom
(later became an Auror and Professor of Herbology at Hogwarts)

House: Gryffindor
Talent: Herbologoy

Wand: Cherry, 13", unicorn hair

Son of Frank & Alice Longbottom (members of Order of the Phoenix).

Other facts: When faced with a boggart, it takes the shape of Severus Snape.

Fred Weasley (killed in an explosion in the battle at Hogwart's)

House: Gryffindor
Talent: Charms and spell inventions
Beater of the Gryffindor Quidditch team.

Son of Arthur & Molly Weasley (members of Order of the Phoenix)

Run a joke store, Weasleys' Wizarding Wheezes, in Diagon Alley.

George Weasley

House: Gryffindor
Talent: Charms and spell inventions
Beater of the Gryffindor Quidditch team.

Son of Arthur & Molly Weasley (members of Order of the Phoenix)

Run at joke store, Weasleys' Wizarding Wheezes, in Diagon Alley.

Luna Lovegood

House: Ravenclaw
Talent: Magical device inventor

Patronus: Hare

Daughter of Xenephilious Lovegood, editor in chief of The Quibbler.

Albus Percival Wulfric Brian Dumbledore (killed by Severus Snape)
Former headmaster at Hogwarts School of Witchcraft and Wizardry

House: Gryffindor
Talent: Magic mastery and Genius-level intellect

Wand: 15", Elder, Thestral tail hair core
Patronus: Phoenix

Dumbledore is considered the best student in Hogwart's history.

Dumbledore was the founder and leader of the Order of the Phoenix.

Significant other: Grindelwald (crush)

Other facts: When faced with a boggart, it takes the shape of his sister Ariana's corpse.

Severus Snape (killed by Voldemort)
Former headmaster at Hogwarts School of Witchcraft and Wizardry

House: Slytherin
Talent: Potions, Legilimency (especially Occlumency) and Dark arts

Patronus: Doe (as Lily's)

Snape is a former Death Eater who is now loyal to Dumbledore and the Order of the Phoenix.

Significant other: Lily Potter (crush)

Sirius Black (killed by Bellatrix Lestrange)

House: Gryffindor
Talent: Nonverbal magic

Wrongly imprisioned in Azkaban for 12 years.

Sirius is an Animagus and take the form of a big black dog (nicknamed Padfoot).

Remus Lupin (killed in the battle at Hogwarts)
Former Defense against the dark arts teacher at Hogwarts

House: Gryffindor
Talents: Nonverbal and wandless magic, and Defence against the dark arts

As a child, Remus was bitten by the Fenrir Greyback, and became a werewolf.

Significant other: Nymphadora Tonks (wife)

Other facts: Remus was nicknamed Moony by his friends. When faced with a boggart, it takes the shape of a full moon.

Nymphadora Tonks (killed in the battle at Hogwarts)
Auror

House: Hufflepuff
Talent: Defence against the dark arts and Duelling

Tonks is a Metamorphmagus, and can change her appearance at will.

Significant other: Remus Lupin (husband)

Other facts: Tonks's Patronus is a werewolf (because of her love for Remus)

Rubeus Hagrid
Former Care of magical creatures teacher at Hogwarts

Hagrid was kicked out of Hogwarts and is not allowed to do magic.

House: Gryffindor
Talent: Care of magical creatures

Hagrid is half gigant, and is resistant to stunning spells.

Alastor "Mad-Eye" Moody (killed by Death Eaters while moving Harry to safety place)
Auror and former teacher of Defence against the dark arts at Hogwarts

Talents: Defence against the dark arts and Duelling

Arthur Weasley
Works at the Ministry of Magic

House: Gryffindor
Talent: Charms

Patronus: Weasel

Significant other: Molly Weasley (wife)

Molly Weasley

House: Gryffindor
Talent: Household spells, Healing and Charms

Significant other: Arthur Weasley (husband)

Other facts: When faced with a boggart, it shows the death of her family and Harry.

William Arthur "Bill" Weasley
Curse-breaker at Gringotts

House: Gryffindor
Talent: Defence against the dark arts

Bill was bitten by Fenrir Greyback, but suffers from only partial lycanthropy contamination.

Significant other: Fleur Delacour (wife)

Fleur Delacour

Fleur went to Beauxbatons Academy in France.
Talent: Charms

Wand: Rosewood, 9½", Veela hair core

Fleur's grandmother was a vila.

Significant other: Bill Weasley (husband)

Charlie Weasley
Works as a Dragon keeper in Romania

House: Gryffindor

Wand: Ash, 12", unicorn tail hair

Kingsley Shacklebolt
Auror

Talent: Defence against the dark arts and Duelling

Patronus: Lynx

Professor Minerva McGonagall
Headmistress at Hogwarts School of Witchcraft and Wizardry

House: Gryffindor
Talents: Duelling, Transfiguration and Nonverbal magic

Wand: 16 1/2"
Patronus: Cat

McGonagall is an Animagus, and can turn into a cat at will.

Aberforth Dumbledore
Owner of the Hog's Head

Talent: Duelling

Patronus: Goat

James Potter

House: Gryffindor
Talents: Duelling and Transfiguration

Wand: Mahogany, 11"
Patronus: Stag

James is an animagus, and can take the form of a stag.

Significant other: Lily Potter (wife)

Other facts: His friends nicknamed him Prongs.

Lily Potter

House: Gryffindor
Talent: Potions and Duelling

Wand: Willow, 10¼", swishy
Patronus: Doe

Significant other: James Potter (husband)

Tom Marvolo Riddle a.k.a. Lord Voldemort (killed by Harry Potter)

House: Slytherin
Talents: Magic mastery and Mastery of dark magic

Wand: 13½", Yew, phoenix feather core

Other facts: Voldemort speaks Parseltongue.

Bellatrix Lestrange

House: Slytherin
Talent: Mastery of dark magic

Wand: Walnut, 12¾", dragon heartstring

Draco Malfoy

House: Slytherin
Talent: Occlumency

Wand: Hawthorn, 10", unicorn hair

On the Slytherin Quidditch team.

Other facts: Draco isn't able to produce a Patronus charm.

Lucius Malfoy
School governor of Hogwarts

House: Slytherin
Talent: Duelling and Potions

Wand: Elm, dragon heartstring

Significant other: Narcissa Malfoy (wife)

Peter Pettigrew (killed by Voldemort)

House: Gryffindor
Talents: Blasting curse

Wand: Chestnut, 9¼", dragon heartstring

Peter was a Animagus and could take the form of a rat. He was nicknamed Wormtail.

He was the secret-keeper of James & Lily Potter.

For 12 years Peter posed as Ron's pet rat Scabbers.

Fenrir Greyback

Fenrir is a werewolf.

Talent: Non-verbal magic

Bartemius "Barty" Crouch, Junior (received the Dementor's Kiss)

Talent: Unforgiveable curses and Transfiguration

Son of Barty Crouch Sr of the Ministry of Magic.

Regulus Arcturus Black

House: Slytherin

Seeker of Slytherin Quidditch team.

Regulus was a Death Eater, but regretted it and tried to bring Voldemort down.

Dolores Jane Umbridg
Senior Undersecretary to the Minister for Magic

House: Slytherin (?)
Talents: Offensive and defensive magic

Wand: Unusually short
Patronus: Long-haired cat

Cornelius Oswald Fudge
Former Minster for Magic

Talent: Transfiguration

Bartemius "Barty" Crouch, Senior (killed by his own son)
Former Head of the Department of Magical Law Enforcement

Talent: Memory charm and Imperius curse

Percy Weasley
Former assistant to Barty Crouch Sr.

House: Gryffindor
Talent: Transfiguration

Xenophilius Lovegood
Editor of The Quibbler

House: Ravenclaw (?)

Sybill Trelawney
Professor of Divination at Hogwarts

Talent: Predictions

Sybill was the one who made the prediction about Harry.

Horace Slughorn
Positons master of Hogwarts

House: Slytherin
Talents: Potions, Occlumency and Transfiguration