Mr. Norris is the 'Janitor' of Hogwarts School. He hates the students with a passion, and wants to do everything to make them feel rotten. He is also accompanied by his cat(?) Filch.
Role in the story
Mr Norris first appears when Ebony and Vampire are chasing down Draco, who is angsting about something. He loudly asks if there is anyone nearby whilst waving around a flashlight. Filch makes his way under Vampire's Invincibility Coke, which is apparently visible, and meows. Inexplicibly, Vampire frenches Ebony just as Mr Norris pulls off the cloak and they run away.
Mr Norris is mentioned as looking happy when Lucian and Sirius are rescued.
Lastly, Mr Norris arrives with Lupin after Britney frees the latter from 'Azerbaijan'. He expresses his hatred for Hogwarts students, claiming that his job would be great without them, then runs away when Ebony casts a spell on Lupin.
Difference from the Original
Hogwarts has no janitor, but a caretaker. The caretaker is called Argus Filch and the cat Mrs. Norris.
It seems reviewers pointed out this mistake to Tara, as in her next author's note:
I no itz mr. noris itz raven’s folt ok!11 u suk!1 no jus kidding raven u fokieng rok prepz suk!1