There is always that one guy that makes the whole school feel like a haunted house. In most occasions, it's either a professor or the school caretaker giving some weird vibes and looking at you in a weird way. In Harry Potter: Hogwarts Mystery mobile game that will be the case with Argus Filch.
Argus Filch was born in the late 1950's somewhere in Great Britain. He came from a family of wizards but he got really unlucky. When he was a kid he was so excited about becoming a wizard but when he first tried to wield magic, nothing happened. Therefore, he realized he was one of the rare sorts of half-blood's that have the predisposition to do magic but that for some unknown reason can't. That kind of "wizards" are called Squibs, they are the same thing as Muggles. This made him so frustrated and angry but he had to move on. He still wanted to be around magic so he attended Hogwarts School of Witchcraft and Wizardry. There he got the job as school caretaker around 1973. He surely did his job very well, succeeding every other caretaker that worked before him. But and there is always a but, he despised kids. He was so full of hate towards kids, especially towards younger new students. Mostly because he was kind of jealous. He showed his anger in a really bad way. He was lurking all students in hallways, mostly at night looking for ways to put kids in detention even if they don't deserve it. His appearance was like his personality. Always grumpy and arrogant. He also had a trustworthy companion that rarely left his side. A cat named Mrs. Norris who was very attached to him. She also had a deep connection with her master and she was also looking for troublesome kids. In the game, you will see Filch and his cat on few occasions, mostly when it gets to some forbidden topics because Filch is always patrolling Hogwarts castle and he knows every room and every secret that is lying there.
Chapter 6: You will first see Mr. Filch in halls of Hogwarts after your illegal duel with Merula Snyde. There he will interrupt your conversation with Professor Snape and he will tell Snape that he is urgently needed because something happened with the Cursed Vaults.
Chapter 9: Even tho you saw Argus Filch while you were talking to Snape he will personally approach you later on near the end of year 1 where he will be wonder where were you going at that moment. There he will figure out you are Jacob's brother and he will start shouting that you are like your brother and that he should punish you while he still has the chance.