Question: Who does the double-agent of Hogwarts's headmaster love?

full_context: Document 1: List of supporting Harry Potter characters: The following are supporting characters in the "Harry Potter" series written by J. K. Rowling. For members of the Order of the Phoenix, Dumbledore's Army, Hogwarts staff, Ministry of Magic, or for Death Eaters, see the respective articles.
Document 2: Severus Snape: Severus Snape is a fictional character in J. K. Rowling's "Harry Potter" series. An exceptionally skilful wizard, his coldly sarcastic and controlled exterior conceals deep emotions and anguish. A Professor at Hogwarts School of Witchcraft and Wizardry, Snape is hostile to the series' protagonist, Harry, the moment he sets foot in Snape's classroom; this hostility is rooted in Harry's resemblance to Harry's father James, who bullied and harassed Snape during their time at Hogwarts. Though philosophically attracted to the Dark Arts and Lord Voldemort's ideology of wizard supremacy, Snape's love for Muggle-born Lily Evans, Harry's mother, eventually compels him to defect from the Death Eaters. Snape becomes a double-agent on behalf of Albus Dumbledore and the Order of the Phoenix, and protects Harry throughout the series.
Document 3: James Potter (series): The James Potter series is an unofficial sequel-series of J.K. Rowling's Harry Potter universe, written by G. Norman Lippert. The novel series centers around the character of James Sirius Potter, Harry Potter's son, a character who makes a fleeting appearance in the novel "Harry Potter and the Deathly Hallows". The series starts with his first year at Hogwarts, set one year before the end of the Harry Potter series.
Document 4: Harry Potter (character): Harry James Potter is the title character and protagonist of J. K. Rowling's "Harry Potter" series. The majority of the books' plot covers seven years in the life of the orphan Potter, who, on his eleventh birthday, learns he is a wizard. Thus, he attends Hogwarts School of Witchcraft and Wizardry to practise magic under the guidance of the kindly headmaster Albus Dumbledore and other school professors. Harry also discovers that he is already famous throughout the novel's magical community, and that his fate is tied with that of Lord Voldemort, the internationally feared Dark Wizard and murderer of his parents, Lily and James.
Document 5: Severus Snape and the Marauders: Severus Snape and the Marauders is a 2016 American short film written by director Justin Zagri, based on "Harry Potter" characters by J. K. Rowling. It officially premiered on March 1, 2016 at the Youtube channel Broad Strokes Productions. The fan film caught the attention of BuzzFeed, "Entertainment Weekly", "Time",
Document 6: Dumbledore's Army: Dumbledore's Army (or D.A. for short) is a fictional student organisation in J. K. Rowling's "Harry Potter" series that is founded by the main characters, Harry Potter, Ron Weasley and Hermione Granger, to stand up against the regime of Hogwarts High Inquisitor Dolores Umbridge, as well as to learn practical Defence Against the Dark Arts. It was founded in the fifth book, "Harry Potter and the Order of the Phoenix". Cho Chang conceives of the abbreviation "D.A." and Ginny Weasley conceives of the name "Dumbledore's Army".
Document 7: Elizabeth Burke: Elizabeth Burke, (fictional) Headmaster at Hogwarts by JK Rowling
Document 8: Potions in Harry Potter: This is a list of potions used in the "Harry Potter" series. Many are mentioned in potions class at Hogwarts, which is taught by Severus Snape in books one to five and Horace Slughorn in books six and seven.
Document 9: Harry Potter and the Philosopher's Stone: Harry Potter and the Philosopher's Stone is the first novel in the "Harry Potter" series and J. K. Rowling's debut novel, first published in 1997 by Bloomsbury. It was published in the United States as Harry Potter and the Sorcerer's Stone by Scholastic Corporation in 1998. The plot follows Harry Potter, a young wizard who discovers his magical heritage as he makes close friends and a few enemies in his first year at the Hogwarts School of Witchcraft and Wizardry. With the help of his friends, Harry faces an attempted comeback by the dark wizard Lord Voldemort, who killed Harry's parents, but failed to kill Harry when he was just 15 months old.
Document 10: Rubeus Hagrid: Rubeus Hagrid is a fictional character in the "Harry Potter" book series written by J. K. Rowling. He is introduced in "Harry Potter and the Philosophers Stone" as a half-giant and half-human who is the gamekeeper and Keeper of Keys and Grounds of Hogwarts, the primary setting for the first six novels. In the third novel "Harry Potter and the Prisoner of Azkaban", Hagrid is promoted to Care of Magical Creatures teacher, and is later revealed to be a member of the Order of the Phoenix.
Document 11: Lord Voldemort: Lord Voldemort ( , or in the films; born Tom Marvolo Riddle) is a fictional character and the main antagonist in J. K. Rowling's series of "Harry Potter" novels. Voldemort first appeared in "Harry Potter and the Philosopher's Stone", which was released in 1997. Voldemort appears either in person or in flashbacks in each book and its film adaptation in the series, except the third, "Harry Potter and the Prisoner of Azkaban", where he is only mentioned.
Document 12: Harry Potter and the Half-Blood Prince: Harry Potter and the Half-Blood Prince is the sixth and penultimate novel in the "Harry Potter" series, written by British author J. K. Rowling. Set during protagonist Harry Potter's sixth year at Hogwarts, the novel explores the past of Harry's nemesis, Lord Voldemort, and Harry's preparations for the final battle against Voldemort alongside his headmaster and mentor Albus Dumbledore.
Document 13: John Nettleship: John Lawrence Nettleship (1 August 1939 – 12 March 2011) was a British schoolteacher who taught chemistry at Wyedean School, Gloucestershire. His pupils there included Joanne Rowling, whose mother worked for some time as an assistant in his department. He has been stated to be a major inspiration for the character of Severus Snape in Rowling's "Harry Potter" series of fantasy books.
Document 14: Albus Dumbledore: Professor Albus Percival Wulfric Brian Dumbledore is a fictional character in J. K. Rowling's "Harry Potter" series. For most of the series, he is the headmaster of the wizarding school Hogwarts. As part of his backstory, it is revealed that he is the founder and leader of the Order of the Phoenix, an organisation dedicated to fighting Lord Voldemort.
Document 15: Order of the Phoenix (fictional organisation): The Order of the Phoenix is a secret organisation in the "Harry Potter" series of fiction books written by J. K. Rowling. Founded by Albus Dumbledore to fight Lord Voldemort and his followers, the Death Eaters, the Order lends its name to the fifth book of the series, "Harry Potter and the Order of the Phoenix".
ground_truth: Lily Evans