Silverbirch set a challenge at the Harry Potter Fanfiction Challenges Forum to explain how Mrs norris got her name. The bunny bit, and would not let me alone until I wrote this.

Hope you enjoy it!

The First Mrs Norris

Everyone thinks that it must be so wonderful to be a twin. "Always having someone by your side." "Having someone who understands how you think." "Never being on your own." "Having a ready-made best friend." Believe me, I've heard them all.

But it's not true. Not for me – for us – anyway.

I am a twin. You probably never knew that. You probably never thought of me as having any relatives at all, but of course I had. Same as you; same as everyone else. Even Squibs have families – well, they'd have to, wouldn't they? Wouldn't be Squibs if we didn't have nice respectable wizarding families to let down. I had a family – mother, father, two older sisters, twin brother – and me. The unexpected final child. The let down.

Apparently no one knew my mother was carrying twins. Out came Anton, handsome and yelling, and then a few minutes later me, wrinkled and quiet and having to be revived. I wonder sometimes if my parents thought later that it would have been better if they hadn't bothered.

My brother, of course, received the name they had picked out. Anton, after our great great grandfather, who was Minister for Magic in the 1830s. Anton sounds like a great wizard. Either that or a Muggle movie star. I, the unexpected, received the hastily thought up second-best name – Argus. Like a Muggle oven or a catalogue full of cheap tat. Prophetic that. Though, of course, they couldn't have known.

We were identical in every way. In every way but one – the one that mattered. Anton's magic was of the best. Mine was non-existent. I was a Squib. It took our parents a few years to notice. Anton and I were always together, so the accidental magic he did as a child might has easily have been mine. And then I think they suspected for a while before they said anything. I think perhaps they thought that if they ignored it, the problem would go away.

It was my mother's best friend, Mrs Norris who finally got it out into the open.

"That boy's a Squib," she told my mother one day, decisively but not unkindly, as she sat with her on the porch, while Beatrice and Anton played their version of Quidditch on the lawn, Christiana read her Muggle romance novel under the tree and I sat in the tree trying to pretend that I was invisible. Everyone was happier when I wasn't around, and I knew it. I was eight.

Mother burst into tears and made noises about, "How can you say such a thing?" but did not protest too much. She knew that what Mrs Norris said was true.

Mrs Norris was my mother's best friend. They had met on their first day at Hogwarts, had both been sorted rapidly into Hufflepuff, and had been friends ever since. Mother called her Gladys, but no one else called her anything but Mrs Norris. It was as if her marriage to the Muggle Robert Norris defined her utterly. Like my mother, she was not the most able of witches, but unlike my mother she had not the advantages of money and good family behind her to help her to a suitable marriage despite her shortcomings. But she seemed to be happy living more than half her life in the Muggle world. Mr Norris, on the few occasions I met him, was a kindly cheerful man who clearly adored his wife, even if he was somewhat bemused by her on occasion.

I liked Mrs Norris. She was one of the few people in my small world who took as much interest in me as in my brother and sisters. And she was the only person who ever bothered to listen to what I had to say.

In those days, Squibs were something to be ashamed of. No good family would admit to having one in their ranks. Excuses were made – illness, delicacy – for the child not going to school and rarely being seen in public. We were hidden away, forgotten where possible, left to scramble ourselves into what little learning – magical or otherwise – we could manage. You know this of course – everyone knows the story now of poor Ariana Dumbledore. I was another like her. Best forgotten, denied by those who should have loved me best. The misfit. The reject.

These days of course, things are handled better. There are programmes for integrating people like me into Muggle society. It is no longer polite to call us Squibs. We are "magically disabled people", as if a different form of words makes the predicament any easier.

But in those days, when I was growing up, we were Squibs, and barely regarded as human at all. From the time my diagnosis (that was the word they used) was confirmed by the Healer at St. Mungo's and the Inspector from the Ministry, my father did his best to pretend that I did not exist, that he had only one son. He literally ignored me – I could be in the room with him for hours at a time without him once meeting my eyes or saying a word to me.

Anton treated me much the same. Even as small boys, we had never got on well, despite our twinship. Now I was confirmed as defective, second-rate, he seemed to regard me as some sort of pale imitation of himself, like a shadow, that was there but not really necessary. Something to be ignored. The girls were kinder, treating me as a sort of cross between a pet and a servant, although they would never admit at school or elsewhere that they had two brothers. And my mother fed and clothed me, and tried to talk to me, but never once looked me in the face or touched me once what I was was confirmed. I think she blamed herself, thought that her own lack of magical ability had somehow been magnified in me. From a conversation I overheard when I was fourteen, it seemed that my father agreed with her. They separated soon afterwards – in the proper discreet wizarding way of course – Father taking rooms in London "to be nearer his work at the Ministry", and Mother remaining with me in the big house in the country.

My sisters and brothers were all away at school of course, and I lived a solitary existence. My physical needs were cared for, but I could go for days at a time without a word being spoken to me. My mother considered that by feeding me, clothing me and giving me house room that she was doing her duty.

The highlights of my drab lonely existence were when Mrs Norris came to visit. She made a point of seeking me out – I spent a lot of time alone in the tree house that father had conjured for us when we were small children, or in the kitchen where it was warm, and where the House Elves tolerated my presence without openly acknowledging it. She would talk to me as if I mattered, bring me gifts – I remember a soft woollen scarf, a Muggle football, comics where the pictures did not move, sweets and biscuits. She was the closest thing to a friend I had.

My seventeenth birthday came and went unacknowledged. Anton received the traditional watch that is given to a wizard when he comes of age. I did not.

By this time, Christiana was suitably married, and already pregnant with her first child. She took after our mother in having looks but no great magical ability, and like our mother she had family name and money behind her to find her a suitable match.

Beatrice, three years older, was not married. She was rapidly rising through the ranks of junior undersecretaries at the Ministry, and was spoken of as a Junior Assistant to the Minister himself in the not too distant future. Mother called her "a career witch" – an unusual thing in those days – and whispered that there were witches for whom marriage was not "appropriate". I was in my mid-twenties before I put that remark together with the suspicion that Beatrice's constant companion Loretta might be more than a friend, and realised the truth about my sister. It seemed I was not the only oddity in the family, but her oddness was easier to hide behind a façade of respectability.

Anton left school with his ten "Outstanding" OWLs and six top-grade NEWTs and went straight to a desk at the Ministry. You will have heard of him; he is an important man now - Anton Newbury-Filch. He took his wife's name and hyphenated it with ours. So much more distinguished sounding than "Filch" alone. I doubt if the thought crosses anyone's mind that the two of us may be connected, let alone brothers, twins.

It was Mrs Norris who got me the position at Hogwarts. I was twenty-one, idling my time away, increasingly bitter and lonely. Mrs Norris decided to take a hand. My parents were clearly no going to do anything about me.

"Daphne," Mrs Norris told my mother sternly. "That boy needs an occupation. I shall write to Professor Dumbledore about him."

"D-Dumbledore?" Mother stuttered. "But Gladys, dear, Argus is a Squib." She whispered the last word as though it were indecent, even though there was no one there but the two of them (and myself skulking on the terrace listening.)

"I know, but he needs taking in hand. Dumbledore will know what to do. I will write tonight." There was no arguing with Mrs Norris when she was in that mood. She was an inveterate letter-writer. If she saw something wrong, she would write letters until it was sorted out. Professor Dumbledore, the editor of the Muggle newspaper The Telegraph, the Head Goblin at Gringotts, the Minister himself – as far as she was concerned, what she had to say was important, and she would write to "whoever it takes" to get results.

And, as you will have realised, her letter to Professor Dumbledore did get results in my case. Within two months of the overheard conversation, I was established as caretaker at Hogwarts School of Witchcraft and Wizardry, with my own bedroom, my own office, and power of a sort. I have to admit that it is probably not the course I would have chosen for myself. To see the young witches and wizards with the abilities I lack, that were denied me by the accident of my birth, still stings, even after a lifetime of it. But I have food and warmth and shelter, some limited human company, a place in the world.

And, thanks to Mrs Norris, I have a companion, a true friend. Gladys Norris was ill, although not even my mother knew it. She died just a week after I arrived at Hogwarts. I found out in a terse note from my mother, delivered one cold wet morning with a basket containing a tiny mewling tabby kitten. There was a letter attached to the basket from Mrs Norris herself.

Argus,

I know I will not live to see you again, and I am sorry. Try not to be bitter towards your mother and father: they did not know how to treat you better. Our society does not yet allow it. I hope that things will change for the better in your lifetime.

I know that you are a lonely man, so please accept this small gift from someone who has been glad to call herself your friend. I hope she will be a companion and a comfort to you.

G.M. Norris (Mrs.)

It may seem presumptuous but I named the cat after my first – my only – friend. The second Mrs Norris has been my companion and comfort ever since, as her namesake hoped. There must be some of the Kneazle in her, together with some spell – no ordinary cat would have lived so long. We have grown old together.

And we will die together. Dumbledore promised me that if I died first (Squibs do not live as long as wizards, as you may know), that he would deal with Mrs Norris for me. I know that Professor McGonagall will do the same.

And if I outlive her – well, it will not be for long. I have a potion I took from Horace Slughorn long ago that will do what is necessary.

I have had two true friends in my life, both called Mrs Norris.