Hermione Jean Granger ( /hərˈmaɪ.əni ˈdʒiːn ˈɡreɪndʒər/) is a fictional character and one of the three protagonists (the other two being Harry Potter and Ron Weasley) of J.K. Rowling's Harry Potter series. She initially appears in the first novel, Harry Potter and the Philosopher's Stone, as a new student on her way to Hogwarts. After Harry and Ron save her from a mountain troll in the girls' toilets, she becomes close friends with them and often uses her quick wit, deft recall, and encyclopaedic knowledge to help them. Rowling has stated that Hermione resembles her at a younger age, with her insecurity and fear of failure.

Hermione is a Muggle-born Gryffindor student, and the best friend of Harry Potter and Ron Weasley. J.K. Rowling states that she was born on 19 September 1979 and she was nearly twelve when she first attended Hogwarts. She is an overachiever who excels academically, and is described by Rowling as a "very logical, upright and good" character. Rowling adds that Hermione's parents, two Muggle dentists, are a bit bemused by their odd daughter but very proud of her all the same." They are well aware of the wizarding world and have visited Diagon Alley with her. Rowling has described the character of Luna Lovegood as the "anti-Hermione" as they are so different. Hermione's foil at Hogwarts is Pansy Parkinson, a female bully based on real-life girls who teased the author during her school days.

Emma Charlotte Duerre Watson (born 15 April 1990) is an English actress and model.

Watson rose to prominence playing Hermione Granger in the Harry Potter film series. Watson was cast as Hermione at the age of nine, having previously acted only in school plays. From 2001 to 2011, she starred in all eight Harry Potter films alongside Daniel Radcliffe and Rupert Grint. Watson's work on the Harry Potter series has earned her several awards and more than £10 million. She made her modelling debut for Burberry's Autumn/Winter campaign in 2009.

In 2007, Watson announced her involvement in two productions: the television adaptation of the novel Ballet Shoes and an animated film, The Tale of Despereaux. Ballet Shoes was broadcast on 26 December 2007 to an audience of 5.2 million, and The Tale of Despereaux, based on the novel by Kate DiCamillo, was released in 2008 and grossed over US $86 million in worldwide sales.

Emma Watson was born in Paris to Jacqueline Luesby and Chris Watson, both British lawyers. Watson has one French grandmother, and lived in Paris until the age of five. Following her parents' divorce, she moved with her mother and younger brother to Oxfordshire.

Rupert Alexander Grint (born 24 August 1988) is an English actor, who rose to prominence playing Ron Weasley, one of the three main characters in the Harry Potter film series. Grint was cast as Ron at the age of 11, having previously acted only in school plays and at his local theatre group. From 2001 through 2011, he starred in eight Harry Potter movies alongside Daniel Radcliffe and Emma Watson.

Beginning in 2002, Grint began to work outside of the Harry Potter franchise, taking on a co-leading role in Thunderpants. He has had starring roles in Driving Lessons, a dramedy released in 2006, and Cherrybomb, a small budgeted drama released in 2010. Grint co-starred with Bill Nighy and Emily Blunt in Wild Target, a comedy. His first project following the end of the Harry Potter series will be Into the White, a 2012 anti-war release in which he stars as the main role.

Rupert Alexander Grint was born and raised in Hertfordshire, England, United Kingdom. His mother, Joanna Grint (née Parsons), is a housewife, and his father, Nigel Grint, is a memorabilia dealer. Grint is the eldest of five siblings. He attended St Josephs Primary School in Hertford, a Roman Catholic primary school. While there, Grint took an avid interest in theatre. He started performing in school productions and joined the Top Hat Stage and Screen School, a local theatre group that cast him as a fish in Noah's Ark and a donkey in another nativity play. He continued performing in school plays as he moved up to Richard Hale School. However, Grint had never acted professionally before the Harry Potter series. At the age of 16, he left school to focus on his acting career. "I didn't really like school that much," the actor later commented.

Ronald Bilius "Ron" Weasley is a fictional character and one of the three protagonists (the other two being Harry Potter and Hermione Granger) of J. K. Rowling's Harry Potter series. His first appearance was in the first book of the series, Harry Potter and the Philosopher's Stone as the best friend of Harry Potter and Hermione Granger. He is a member of the Weasley family, a pure blood family, who reside in "The Burrow" outside Ottery St. Catchpole. Along with Harry and Hermione, he is a member of the Gryffindor house. Ron is present in most of the action throughout the series due to his friendship with Harry.

According to J. K. Rowling, Ron was among the characters she created "the very first day". Ron is inspired by Rowling's best friend Sean Harris (to whom Harry Potter and the Chamber of Secrets is dedicated), but she has clearly stated that she "never set out to describe Sean in Ron, but Ron has a Sean-ish turn of phrase." Like Harris is to Rowling, Ron is "always there" when Harry needs him. The character of Ron fits many of the stereotypes expected of the sidekick; he is often used as comic relief, is loyal to the hero, and lacks much of the talent Harry possesses, at least in terms of magical power. However, he has demonstrated bravery several times, such as playing 'real wizard's chess' in the first book, and entering into the Forbidden Forest with Harry during the second book despite his arachnophobia.

Severus Snape is a fictional character in the Harry Potter book series written by J.K. Rowling. In the first novel of the series, he is hostile toward Harry and is built up to be the primary antagonist until the final chapters. As the series progresses, Snape's character becomes more layered and complex. Rowling does not fully reveal the details of his true loyalties until the end of the final book, Harry Potter and the Deathly Hallows. Over the course of the series, Snape's portrayal evolves from that of a malicious and partisan teacher to that of a pivotal character of considerable complexity and moral ambiguity. Snape primarily teaches Potions at Hogwarts, though in the sixth novel he teaches Defence Against the Dark Arts, a position which he was known to have desired throughout the series. He ultimately becomes Headmaster of Hogwarts in the final novel. Rowling has described him as "a gift of a character".

In an interview, Rowling described Snape's character as an "antihero". She has said that she drew inspiration for Snape's character from a disliked teacher from her own childhood, and described Snape as a horrible teacher, saying the "worst, shabbiest thing you can do as a teacher is to bully students." However, she does suggest in the books that he is generally an effective teacher. Although Rowling has said that Gilderoy Lockhart is her only character that she "deliberately based on a real person", Snape was reportedly based, at least in part, on John Nettleship, who taught Rowling chemistry and employed her mother as an assistant at Wyedean School near Chepstow. For Snape's surname, Rowling borrowed the name from the village of Snape, Suffolk. In a 1999 interview, and again in 2004, Rowling singled out Snape as one of her favourite characters to write.