Prologue:
Once upon a time, long after Katherine had left his life, and before Elena stepped in, there was another young girl that held Damon to this world.
She's the reason he has a hard time believing Elena thinks he can be saved, even though he so very much wants to.
She's the reason he drinks human blood, embracing his vampirism, instead of living the way Stefan does. Damon knows that he doesn't have the luxury of letting his guard down. Soon, Stefan will see that too, even if he ends up learning the hard way, like Damon did.
She's the reason for his cynicism, his sarcasm, and his complete disregard for human life.
She's his reason for everything.
Elena once told Stefan, that heartbreak over Katherine might be good for him. That maybe it would remind him that he actually had a heart. Elena doesn't know. She doesn't know that he's reminded of the heart he refuses to acknowledge every day.
Because every day when he gets up in the morning, and watches the sun rise, he knows she's no longer there to see it with him. And that hurts more than being shot in the heart with bullets filled with vervain.
Damon didn't know that he could care so much. He didn't know that one little girl could get under his skin as thoroughly as she did. He didn't know that he could love anyone as much as he loved her. Maybe he even loved her more than Katherine.
Fifteen years to a vampire is nothing. A blip of a second really. But with her, fifteen years seemed both like forever, and not nearly long enough.
Damon never wanted anything, in life or death, besides Katherine. But she showed him a whole slew of possibilities, and suddenly, Damon found himself wanting more. He wanted a future with her in it. He wanted to show her the world. He wanted her to fall in love, get married and have a whole pack of kids. He wanted to watch her have every experience that he never got to have...and then some.
Apparently that was too much to ask.
Damon never fully believed in the 'happily ever after' that usually followed 'once upon a time'. But she did. With her bright eyes, warm smile and unending optimism, she encouraged Damon to believe too. And little by little, he did. With her, anything seemed possible. Even that so-called fairy tale ending, with princesses locked in towers, and white knights riding in to save the day.
Looking back, he knows he should have known better. He should have walked away from the very beginning. He should have walked away before she'd become old enough to figure out what he was.
His whole life is filled with 'should haves'.
But he was selfish, and it cost him his world.
Sometimes though, when he's too drunk to hide from himself anymore, he knows he can't regret the short time he knew her. And he knows that, even though it would kill her, he wouldn't change anything. He knows he wouldn't be able to walk away, if given the chance to do it again.
And that's how he knows she was wrong about him.
He wants her to be right. He wants to be a good person, and to make her proud. Damon knows she would be so disappointed, seeing the things he's done since her. And some how, he can't bring himself to care. He's a vampire. There's no use fighting against it. It never did her any good. Wanting and wishing never do anyone any good.
She's the reason Damon lives in the real world now, where vampires burn in the sun, and human girls die horrible, painful deaths because they're waiting for their hero to rescue them.
She's the reason he knows 'happily ever after' doesn't follow 'once upon a time'.
She's the reason for everything he's become, and everything he knows he's going to be.
She's the reason he's officially declared war on the world.
And he's going to make it burn.
Author's Note: Okay, I know that I'm supposed to be working on 'Things We Lost in the Fire', and I am, I promise. I just watched the whole series of Vampire Diaries, totally fell in love with Damon, and started wondering about why he is the way he is. And then Stefan mentioned they hadn't seen each other in fifteen years, and he looked so sad when he said Elena was his only friend and...the stupid plot bunny bit down so hard it left teeth marks. Sigh. So this is my take on what happened in those fifteen years that he's unaccounted for, and the reason he's hell bent on being all 'diabolical'.
Hope you stick around for the ride. :)