Argus Filch is the squib caretaker at Hogwarts. Being a squib he cannot perform magic so cleans and maintains the castle by hand. He also owns a cat named Mrs Norris who assists him on keeping an eye on students. He is known to be very grumpy and mean to students.
 Character development
Argus Filch took over duties as caretaker of Hogwarts from Apollyon Pringle. Not long after becoming caretaker, he acquired a cat named Mrs. Norris to be his companion and assistant to his duties. He greatly disliked the students and got angry at them over the most minor of things. He was known to patrol the hallways at night to catch any students who were out of bed. Some time during his caretaker years, Filch acquired the Marauder's Map which he kept in his office. During Fred and George Weasley's early years at Hogwarts, they stole the map from Filch's office and used it to their advantage. 
 First book
Filch is been tipped off by Draco Malfoy that someone will be in the trophy room at night, in violation of school rules in Harry Potter and the Philosopher's Stone. Filch (and Mrs. Norris) chase Harry, Ron, Hermione and Neville directly to Fluffy, inadvertently providing Harry with information he needs to keep the Philosopher's Stone from Lord Voldemort.
Later on, Filch is more successful in apprehending Harry in the violation of school rules: when Harry and Hermione take Norbert to the top of the astronomy tower to give him to friends of Charlie Weasley for proper raising, Filch is waiting at the bottom of the stairs, and takes them (along with Draco and Neville, who are also out of bed after hours) to Professor McGonagall.
 Second book
During Harry Potter and the Chamber of Secrets Harry Potter finds out that Filch is a squib after Filch discovers Harry has traipsed mess and muck everywhere! Filch takes Harry to his office to make an example of him by punishing him, when Peeves drops the infamous disappearing wardrobe on the floor of a classroom above Filch's office, while Filch is away Harry reads the contents of an envelope discovering Argus is a Squib, Throughout Harry Potter and the Chamber of Secrets Filch guards the spot where Mrs. Norris was petrified and attemts to erase the message "The Chamber of Secrets has been opened, enemies of the hier, beware" from the wall. When the mandrakes begin to mature, Professor Sprout reassures Filch that he will have Mrs. Norris back in no time.
 Third book
During Harry Potter and the Prisoner of Azkaban, Fred and George Weasely give Harry Potter the Marauder's Map. They say that they nicked it from Filch's office during their first year and that Filch never knew how to work the map.
 Fourth book
During the fourth book, Harry Potter and the Goblet of Fire, while Harry is out after hours he drops his clue (the dragon egg he collected in the first task.) Filch hears the noise and discovers the egg thinking that it was Peeves the poltergeist who stole the clue as Harry is wearing is invisibility cloak and cannot be seen. He was going to use the egg as reason for Peeves to be thrown out of Hogwarts until Snape and Alastor 'Madeye' Moody come along and disrupt his plan.
 Fifth book
Filch found an ally in new Defence Against the Dark Arts teacher Dolores Umbridge during this school year, whose ideas of student discipline matched his own. When she became headmistress he tried to help her as she attempted to reform the school, though she was facing a lot of rebellion, particularly from Filch's least favourite trouble makers, Fred and George Weasley. When they set off fireworks inside the castle Filch attempted to bat them away with his broom, which set on fire. After they let off a Portable Swamp in a corridor Filch sneaked into Umbridge's office looking for a new Approval For Whipping form, something he has wanted for a long time. Fred and George escaped the school in spectacular style however, leaving Filch to punt students across the swamped corridor to their classes. Filch regards Dolores Umbridge as the best thing that ever happened to Hogwarts.
 Sixth book
During Harry Potter and the Half Blood Prince, Filch catches Draco Malfoy out of bounds the evening of Horace Slughorn's Christmas party. Malfoy insists that he was trying to come to the party, but Severus Snape knows that he was not and Harry Potter spies on thier conversation out in an empty classroom.
 Final book
Filch is not seen for most of Harry Potter and the Deathly Hallows because the book does not, for the most part, take place at Hogwarts. However, when the students evacuate Hogwarts, he is seen hobbling down the corridor yelling, "Students out of bed!" He is then sent by Professor McGonagall to find Peeves so he can help in the battle.
 Portrayals within films
Argus Filch was portrayed by David Bradley in all Harry Potter films apart from Harry Potter and the Deathly Hallows: Part 1.
 Outward appearance
Argus Filch is approximately 65 years old. He is rather tall and somewhat thin and stooped, with a craggy, haggard face and long stringy hair hanging from the edges of a receding hairline. He seems riddled with ailments. His stringy hair and faded brown clothes give him the appearance of poverty. He's often seen carrying his cat, Mrs. Norris, which results in his clothes being peppered with cat hair, further reducing his image. Being the lone janitor, Filch is often covered with all sorts of nasty things from attempting to keep Hogwarts as clean as possible.
Mr. Filch relates better to animals and inanimate objects than he does to human beings. His first loyalty is to his cat, Mrs. Norris, and his second is to Hogwarts. During Harry Potter and the Order of the Phoenix, he shifts alliance easily to Dolores Umbridge after Albus Dumbledore's ouster as headmaster, not because of any antagonism between the two men, but because Mr. Filch feels his duty is to the school and office of headmaster (or headmistress), and not to the individual who holds it. However, he seems to take sadistic pleasure in carrying out Umbridge's cruel dictates during her reign of terror.
Mr. Filch is rarely seen without Mrs. Norris, who is a long-haired cat with tabby markings and appears in the films to be at least part Maine Coon or Norwegian Forest cat, although her eyes are red rather than the breed standard gold or green. Mr. Filch is extremely fond of Mrs. Norris, who seems to share his delight in capturing student rulebreakers. In Harry Potter and the Chamber of Secrets, Mr. Filch threatens to kill Harry when he discovers Mrs. Norris suspended, seemingly dead, in a school corridor and Harry standing nearby, because he infers that Harry has murdered her, although in fact she was merely petrified by the baselisk. In the film of Harry Potter and the Goblet of Fire, while most of the other Hogwarts faculty and staff members have joined the students on the dancefloor during the Yule Ball, Mr. Filch stands cuddling Mrs. Norris while swaying happily to the music with his eyes closed, as she purrs loudly and contentedly in his arms.
Albus Dumbledore, Minerva McGonagall and Severus Snape appear to recognize Argus Filch's humanity and always treat him with dignity and respect, even while they are overriding some of the caretaker's decisions. They also make it a point to refer to him as Mr. Filch rather than just Filch as the students do.
 Accomplishments and skills
Filch has the best knowledge of the secret passageways of Hogwarts of anyone except for Fred and George Weasley. He is said to be able to "appear as suddenly as one of the ghosts" when Mrs. Norris catches someone making trouble and goes off to get him.
Filch owns a cat named Mrs. Norris, who assists him in catching school troublemakers. Mrs. Norris would catch students and seconds later Filch would come up right behind her, because he had a very extensive knowledge of the school's passageways. Students hated Mrs. Norris and it is noted in Harry Potter and the Philosopher's Stone that it was many of their dearest ambitions to kick her. During Harry Potter and the Chamber of Secrets the Basilisk petrifies Mrs. Norris, and Filch blames Harry Potter. During Harry Potter and the Order of the Phoenix Peeves shuts Mrs. Norris in suits of armor frequently after the Weasely twins leave the school.
The only known fact about Flich's family is that they are in fact Wizards and Witches, as Filch is a squib.
Argus Filch is mostly well received by audiences. His appeal comes from his lack of magical abilities and his "Igor" like personality, which reveals the sadness that he deals with on a daily basis. He's quite often getting the short end of the stick and has to do the jobs that no one else wishes to do, but are very important to the upkeep of Hogwarts. This results in the audience feeling sorry for Filch quite often. He only wishes to be important to the main story and does in fact achieve an important role in the world of Harry Potter. People always have sympathy for the guy lowest on the totem pole, because everyone has been there at some point in their life.
 In popular culture
If applicable, maybe a couple paragraphs here.
 Additional Canon
It is prefered that you use an Additional Canon section (and related sub-sections) on LeakyPedia entries for information that comes from lesser canon sources such as video games, board games, action figures, amusement parks, and other Warner Brothers or J.K. Rowling sanctioned sources.
 External links
Usually this section is for general but official links here. You may not have an external links since this is a character.