Dennis quite enjoys being a teacher, he realises one day when in his late thirties. It's his life, his love – all he needs to be happy. He'd been young when he accepted the job, and even ten years later he never once doubts that he'd made the right choice.
It was slightly ironic that his worst subject in school was the one he now taught.
He'd hated Charms as a boy. He'd loved the teacher; dear old Flitwick, may he rest in peace, had been a hard teacher to dislike. All the same, the actual subject had been the bane of his life.
He masters Charms while he's away travelling after Hogwarts. Since his second year, he'd been looking forward to the year after Hogwarts when it was something of a tradition to gain some experience in the wizarding world outside of Britain. He'd finally got bored with the safety of Hogwarts and Diagon Alley and wanted some adventure. Even Hogsmeade didn't hold his attention for long after his third year. What he really wanted was to be out there. He wanted to travel the world, doing things few wizards had ever done.
His brother had been of the same mind. He'd even promised Dennis that he'd wait until they'd both got their NEWTS to go, so that they could go together. "I'll get a job in a shop," he'd said. "And then once you're finished, we can both travel!"
That hadn't happened. Instead, Colin fell in the Battle of Hogwarts.
Dennis went anyway, but it wasn't the same. He sees the most wondrous things out there – dragons in Wales, floating pyramids in Egypt, a Native American wizarding ritual in which an entire tribe transforms into bears, even the children. But at each and every sight, he turns to the spot beside him, the spot where Colin should be, and he's struck by how alone he is.
Then he finds himself in Greece, stuck on a mountain trapped under the paw of a manticore. He's as good as dead.
And then, suddenly, he isn't. He's in a cave, having tea with an ancient wizard whose beard is longer than Dumbledore's ever had been. Then, just like that, the wizard is teaching him how to fend off a magical creature without hurting it. And then he's being taught how to magically organise boulders with magic so that no one would notice your presence. And then he's learning how to cast anti-apparation charms.
Next thing he knew, three years had passed and he is supposed to have gone back to England over twenty months ago.
And so he returns, his head stuffed full of spells and knowledge and experience that no wizard can learn from books. But he has a thirst for it now; he needs to learn.
Apparently students aren't supposed to return to Hogwarts at the age of twenty-one. But that wasn't going to stop Dennis. He's never quite certain how he does it, but not long after his return he can be found in the Hogwarts library from Monday to Friday, reading and reading and reading and reading. When he stops, it is only to jot down a few notes before returning to his studies.
He lives on muggle money, which buys him muggle food and muggle housing. With no job to support himself, he becomes a muggle chair supplier; magicking muggle sofas and the like out of blades of grass. It's easy and quick, although he does sometimes wonder whether it could be called 'honest' work.
After only a few years of this, while sitting in the library one day, he is approached by none other than his old head of house. Minerva McGonagall, who has become a fine and famous headmistress in her own right, sits down opposite him and asks him if he can help her renew some of the protection charms placed upon Hogwart's walls. "A lot of them are very complex charms, amongst other sorts of magic, and I'm afraid I was always more interested in Transfiguration than any other branches of magic," she says, by way of explanation.
It isn't until several years later, by which time he is a much-experienced Charms teacher, that he wonders whether her request wasn't simply an excuse to test his skills before offering him the job the very next day.
He watches students pass through the school like they were dandelions being carried through on the evening breeze. He observes his first NEWT class sit their exams, and what was once his Ravenclaw-Hufflepuff second-year class breeze through their OWLS. He first feels his age when those who had originally been his first year Charms students graduate.
And soon he begins to see familiar faces in the halls once more. Familiar, but not familiar, because they are the same but not the same. First there is quiet Teddy, who so much resembles Colin's favourite DADA teacher. He is followed closely by Victoire, who possesses all of her mother's beauty and more besides. Then there's a flood of them; James Potter, who can easily pass for Harry in looks, but with a prankster nature to give the Weasley twins a run for their money; Albus Scorpius, as different from his father as James is alike; Lily Luna, who can't be anyone but Ginny's daughter. Then there are Ron and Hermione's children; smart and bookish and competitive and brash and such a combination of their parents that Colin has to laugh when he first takes the class that the older sister, Rose, is in. And a couple of years later, Hugo is very much the same.
There are more than the Golden Trio's children, though; it is all of the next generation. The offspring of Dumbledore's Army, who Dennis knew that, like him, have travelled far and wide and still returned to their home in the end. There are Seamus' seven Irish children; Susan's twin daughters; many, many more Weasleys (so much so that Dennis occasionally forgot which red-head belonged to which parent). A couple of oddballs pass through Hogwart's spacious halls who are undoubtedly the children of Luna Lovegood, even if they don't bear her last name. There are sons and daughters of Slytherins and Ravenclaws who Dennis has never spoken a word to, but he always gets a sense of de já vu when he first spots them.
His one regret is that he doesn't have any nephews or nieces running around with the rest of them. Dennis doesn't want his own children; he's never met the right lass, or a lass at all for that matter (although he'd met a couple of lovely lads in his younger days), but he wishes that Colin had been able to have that life. He would have made a great father, Dennis knows.
There certainly wouldn't have been a shortage of family photographs.
But it wasn't to be, and gradually the feeling of sadness that always comes with memories of Colin abates. Life continues, classes are taught, and children grow older.
The tide of familiar faces and names slowly ceases, and suddenly he wakes up one morning with nothing but the horrible feeling of age. Of being far older today than he'd been yesterday.
When he looks down at the breakfast hall that morning, he sees four, maybe five, familiar faces of children whose parents he'd fought beside. The last, straggling child of Seamus' large clan, George and Angelina's two children, and a couple of others that are dotted around the place. It makes him think of the people he'd gone to Hogwarts with. It makes him realise the startling truth.
They've all moved on with their lives. They've grown up, gotten jobs, raised families, and lived, free of this castle and the years they'd spent here. Dennis has run back to it at the first opportunity, surrounded by the safety of his memories.
That night, Fred comes to him. Fred, who looks so similar to his namesake, even if his personality isn't anything like that of the deceased man Dennis once admired. He asks for help with the latest charm Dennis has set them (something the entire class is struggling with, now that they are at NEWT level). And Dennis, who's never refused a single student who asks for help, says yes.
It is the only yes he says, but later that night he wishes he'd found it in himself to say no. If not to the plea for tutoring, but to the closeness between them, to the hand on his knee, to the tongue in his mouth. The next night, he wishes he'd said no to the hand on his cock and to the whispered moans of "Oh, God, I need this so much. Do you like this? Yeah… oh, oh oh-"
He knows it is wrong. Never in all his years of teaching has he even entertained the notion of sleeping with his students. Even James, who looked so much like Harry had when they were young. Even Martin, who'd been so vulnerable and disappointed when he'd thrown himself at Dennis, only for the Charms Professor to tell him that it could never happen.
He knows it is wrong, even as his fingers entwine in that red hair, as those perfect lips surround his throbbing cock. It is wrong when they do it in his office; it is wrong when Fred pulls him into a broom closet for a quick handjob. It is even more wrong when the thrill of being caught rushes through him as someone walks past, only a few feet from where the two of them stand with baited breath.
It is wrong, but oh-so right.
He feels like a teenager again, just for those quick seconds when he shoots his load into the mouth of a boy who is barely old enough to apparate. In the moments when he runs his hands all over Fred's gloriously seventeen-year-old body, he feels young. This is what I could have had, he tells himself, had he not taken the job at Hogwarts, or if he'd never met the man with the beard (whose name he never found out). It is what he might have had, but never once does he realise that he does have it right now, because right now is too late. Right now is when he is too old to enjoy it.
It lasts for more than a while; almost six months by the time he summons the strength to end the relationship. It is six months too long, Dennis knows, but at the same time it is an eternity too short. And once it is all said and done, with Fred heartbroken and sworn to secrecy, his bed is colder than it has ever been and the years press on him like he is bearing a mountain on his shoulders.
Fred passes his NEWTS with flying colours, achieving all the grades his father had been too distracted to try for. Dennis is pleased to say that his 'Outstanding' in Charms is not the result of any biased marking on his part.
He teaches for one more year, before handing in his resignation to Susan, who's risen to the position of Headmistress now McGonagall has resigned.
"Why?" she asks, when he hands her the letter. "You love teaching."
"I thought I loved teaching," Dennis corrects her. "I think I might have been wrong."
She allows him to leave it like that, curses him for saddling her with a third empty position to fill for the next year, and wishes him the best of luck for his future.
He expects to step out of the castle and feel an overwhelming sense of freedom. Instead, he just feels lost. Hogwarts has always been his home; since the age of eleven, he's known nowhere else. His muggle flat; the cave with the bearded guy; they were a brief holiday before he returned to where he belonged. But he doesn't belong there anymore.
He gets a job in a shop, serving over the counter. It is owned by a lovely old lady who sells antiques. The job sounds boring, but a lot of the things come to him cursed, so it keeps him on his toes. Soon he is also managing it for her, as her health slowly slips away. And when she dies two years later on her hundredth birthday, he is pleasantly surprised to find she's bequeathed it to him.
For another uneventful year, he is happy. A little lonely at times, but overall, contented. On Sundays he closes up early and heads down to the Three Broomsticks for drinks and to socialise, and once a month he pops into the Leaky Cauldron to see how things are going there.
That is when he runs into Fred Weasley for the first time since leaving Hogwarts.
The boy had been exactly that – a boy – when Dennis last saw him. Since then he's filled out, and grown to tower over his old teacher. He's also grown into that mischievous smile that he'd inherited from his father; if it wasn't for the shade of his skin, the colour of his eyes, and the fact that he still had both his ears, he could be George from a few years after the battle, come forwards in time to see what the future was like.
"Evening, Professor Creevy," Fred says easily, and Dennis wonders if it is just him who feels the lurch of familiarity combined with the rush of shame.
"Professor no longer, m'boy," he says, in an attempt to be jovial. He winces as the "m'boy" comes tumbling from his mouth – he's never referred to anyone as that in his life. "I'm a humble shop keeper nowadays."
"I hadn't heard," Fred says. "I'm sorry to hear you gave it up. You always were my favourite teacher."
And somehow that brief exchange ends them up together in one of the rooms above the leaky cauldron, a sense of post-orgasmic awkwardness slowly descending upon them.
"You've become more experienced," Dennis says, for lack of anything else to talk about.
"I had a bit of practice," Fred replies, not able to look at his former teacher. "You know, with people."
They part in silence after that.
And so Dennis returns to his shop, to his cursed antiques, and to his weekly night out. More years pass; more decades pass, even. Wrinkles begin to appear on his brow – laughter lines, he'd like to claim, only he hasn't done as much laughing as he'd wished – and those creases are accompanied by the occasional silver hair. That's when he stops going to the Leaky Cauldron once a month. He doesn't want Fred to see him, not now.
He hears through the grapevine – Hannah Longbottom's grapevine, to be exact – that Fred is engaged. Not long later, he hears that he's married. To a lovely girl only a few years younger, with a laugh pretty enough to make the birds sing. Those first two times, he struggles to hide his frown.
His business begins to soar, and he sells it soon after. He likes a quiet life, after all. He briefly wonders about moving to France, but he doesn't want to learn the language. Instead he moves to Ireland, only to discover that with their thick accents, he might as well have moved to France. He still goes to the Three Broomsticks every week.
When Hannah tells him George Weasley is going to be made a grandfather by both of his children, Dennis manages a smile. He's surprised to find that it's real.
As more decades pass, Dennis realises that the years of his life are like leaves on an autumn day as he lies on a grassy hill. If he closes his eyes, they blow by without him noticing. Sometimes they make a rustling noise as they skim over green dewy blades. Sometimes he opens his eyes to see them dancing past, always so considerate as they try not to wake him.
He wishes he'd left his eyes open the whole time.
Soon he's standing by gravesides of those he once knew. Not just his muggle family, but the witches and wizards he went to school with. The aurors go first, and the other ones who took dangerous jobs. Then disease takes some more. Soon, there are only a couple of them left – but Dennis isn't sure who, because it's been so long he's forgotten their faces.
When the century turns, Dennis wonders where it all went. He can remember being a teenager like it was yesterday, but the past fifty years have gone by so quickly that you'd miss it if you blinked.
Dennis wonders whether he blinked, and that's why he doesn't remember much of them.
Sometimes he thinks back to that red-head boy he once loved so well – and it must be love, he supposes, because he was certainly the only person Dennis was with for longer than a night. If that was love, though, he doesn't think much of it. He could have just as easily gone without it.
He never expected the day to come when he stands in front of the grave marked Fred Arthur Weasley. Underneath it are the words 'not to be confused with that guy over there' and there's a magical arrow hovering over the stone, pointing to the original Fred's grave.
Dennis thought that Fred probably would have liked that. And then he frowns, because he's not actually sure. Certainly his uncle would have liked it.
The thought disturbs him. He taught him for seven years, and slept with him for six months. It was probably something that Dennis should know. He has a feeling that he might have known once, if only his mind didn't wander so much….
At the funeral are a bunch of red-heads, and Dennis wonders why they all look alike. It's their own fault for being so blurry, he thinks grumpily. The idea that at the age of a hundred, his eyesight might not be what it used to be, doesn't cross his mind.
A week later, Dennis goes to bed and wakes up to find himself sitting in a field of grass, staring back at his fifteen-year-old brother.
It wasn't unexpected, but the first thing he still says is "Damnit."
Colin looks up at him curiously. "Now why would you say that?" he asks.
"I'm dead."
"Just a bit, yeah."
Dennis thinks about this for a few minutes. Without thinking about it, his hands reach down and pluck out blades of grass. Then he asks, "Doesn't make a lot of difference, does it?"
"Whatever do you mean?" Colin replies.
"I can't help feeling I was dead anyway," Dennis replies, looking around. "I just was too slow to realise it."
He realises for the first time that it isn't just him and Colin; sitting by them is a familiar mop of red hair. "Oh," he says belatedly. He looks down, ashamed of how he looks. Fred hasn't seen him in over sixty years.
"Don't worry," Fred laughs, as though he read Dennis' mind. And Dennis realises that Fred should look older too. "We're all the same age here."
"Pity we couldn't be back there," Dennis comments. "I sometimes wondered whether we could properly have sustained a relationship. I didn't think we could. Not with the age gap." He pauses for a moment, then adds for Fred's benefit; "I'm sorry. I wasn't very good to you."
Fred nods graciously, and Dennis knows the apology is accepted.
But the matter isn't over. "Twenty years wasn't much for a hundred-year-old," Colin points out, almost scolding, and suddenly Dennis is ashamed of his entire life. He'd lived for so long and done so little. He could have had a lot more, if he'd tried.
"Twenty years is a lot when one's forty and the other's twenty," Fred points out. "I'm half-glad you didn't let me persuade you to keep things going."
"Shouldn't you be in your own heaven?" Dennis asks. He both longs for and dreads the answer, that this is Fred's heaven. Fred has a wife to spend his afterlife with, but Dennis wishes just a little that he might be granted the same joy.
"I am," Fred says. "But I'm here as well. I can be in lots of places. We have forever to life again, this time without limits. I have to say, I'm looking forward to it."
Dennis wonders how long forever is, and then decides it doesn't matter. It's the best type of afterlife, he thinks to himself. Getting to do everything you couldn't when you were alive.
It doesn't stop him from wishing he has less to catch up on.