This is my favourite stories I have every written. It is a look at B's past and character.

Disclaimer: If Death Note belonged to me, it would be very different.

He could admit it. He was obsessed. He had an obsession with the detective, and it made his heart ache like nothing else.
Which is why he killed. Again, and again. At first it was to fill the emptiness in his heart, the emptiness that A had left. A's death had hurt. Beyond had never known so much pain before. Not when his mother had died; she had been a whiny bitch. Not when his father had died, either; work was more important than his strange son. And with their deaths, he had met A. And A was the best thing that had ever happened to Beyond.
It didn't matter that A was Alpha, that A was first, because A was everything Beyond had ever wanted and ever needed. He was loyal, loving, trusting. He was everything B wasn't.
And Beyond had watched the numbers tick down over A's head every day. And B had known that A's number was far, far smaller than anyone else's. Smaller than Matt and Mello's, whose numbers were freakishly close. Smaller than the strange little albino who sat with his toys in the corner. Smaller than the artist girl who tried to talk to the albino every day. Smaller than her friends, a singing brunette and a ginger sprinter. It had worried him so much that his own personal messiah was going to be snatched away from him. It terrified him like nothing else. Because A was perfect. And A was going to be L one day. He was. B would make sure of that. Even if it meant killing L before A's numbers ran out.
And B was not past doing that for A.
A's name was Aaron Arwin. AA. A knew that B knew his name, and that was fine. Because in return, B had told A his name. As a kind of apology.
It wasn't just the terrible burden of knowing the exact moment everyone around him would die that had driven Beyond insane, even before A was gone, it was the fact that he almost felt guilty that all his fellow students had gone to so much trouble to hide their names, and yet he could see, very easily, their real ones. He felt like he was cheating. And however much B liked to play games, he did not believe in cheating. He would win by fair play, no matter what that fair play was.
He stopped feeling guilty on the day of A's death.
The numbers were down to double digits. B was terrified. A had been getting more and more jittery and timid. Despite the fact that he was the true successor to L, he often told B he was so scared he would get something wrong. B had found him cutting one day, and yelled at him to stop, and A had started crying.
B had felt so, so guilty that his friend's blood had made him feel all tingly and excited inside, like there was some terrible monster inside him that would snap. And he had a horrible feeling that, one day, he would be the one cutting someone's arm. And that thought excited him.
The monster came out of hiding a week later. A girl, taking a walk before bed, had stumbled upon A's body. His eyes were glassy, and he had cuts running up his arms. His mouth was frozen in an expression of relief.
The crowd of children gathered around the body parted as B pushed his way through. He couldn't breath. He couldn't think. The only thought running through his mind was of the jam he and A had stolen from the kitchen the night before. A knew that B loved jam. Normally, he'd have nothing to do with B's jam collecting endeavours, but that night, he'd come with him.
That had also been the night A had kissed him.
"No regrets, Beyond Birthday." A had murmured as he'd got into bed, leaving B shocked and confused. And it took a lot to confuse Beyond Birthday. Why had A done this? Why was he showing... feelings now, of all times? To be honest, B wouldn't have minded if A had kissed him again. A could've kissed B anytime he wanted.
But now it all made perfect, awful sense. Everything, from the jam, to the kiss, the to decreasing numbers over A's head. Aaron Arwin was dead, and he had been planning to be for quite a while.
Beyond had snapped. He was Backup, so he would be next in line, wouldn't he? A had killed himself because he had broken under the burden and expectation of the successorship of L.
So it was L's fault.
So L would pay.
It was a few months before Beyond made his move. He needed something, someplace to go. He made arrangements to leave Wammy's for good on his sixteenth birthday, three months away. He rented a flat in LA in advance, and booked the flight over to America.
Then, one day, a few weeks before the date he was planning to leave, he peeked into Wammy's office, simply because he heard a voice he did not recognise there. A young man with slumped shoulders, spiky black hair and pale skin was standing with his back to the door. Beyond couldn't see his name; he'd have to meet the strangers eyes to do that.
The man turned to the door for a fraction of a second, as if he could sense he was being watched, then quick as a flash, turned around again. It had been too quick to B to catch his whole name, but the first one had been easy enough.
One letter.
L.
B would win.
It was a game, now.
That was when he stopped seeing his eyes as cheats and more as power ups. They were a disadvantage L did not have, and B would use them at every opportunity he had. Because an advantage was an advantage, no matter how strange and obscure it was.
Beyond moved away to LA. He had chosen the place partly because... well, he had read about it when he was younger and it had sounded like his kind of place, and also, the initials were particularly fitting: LA. L's punishment for A's death.
Before the LABB murders began, Beyond needed to experiment.
He also needed to feed the monster he had felt stirring three months ago.
So Beyond Birthday committed his first murder at the age of sixteen.
It wasn't bloody, or particularly gory. He pushed a man off a building. But it made him happy. And, for some reason, that didn't scare him anymore.
He spent a year planning the LABB murders. They were intricate and controlled in every manner, and they were like one huge puzzle. B loved puzzles. He was in control of this, the master, the creator of the board.
He never expected to be beaten at his own game.
But in the end, when he was in prison, with his heart clenching and his mind dying, all he could see was names.
Names. Every name he'd ever watched float above a person's head.
Charity Chase Fabien Davids Goldi Harmen Believe Bridesmaid Nate River Titania Birch
All the names, whether he knew it or not, had been stored away in the back of his genius mind.
Cyril Ellison Artemis Sailor Mail Jeevas Aaron Arwin Angel Oak Lyra Greenpool
He remembered. Every single one of them.
Quarter Queen Erin Finch Darcy Daniels Backyard Bottomslash
In his last few seconds, they came rushing back to him in an endless stream of information.
Miheal Keehl Bluebell Harford Tiffany Birch
As the stream grew less and les prominent, one name became singled out. One he hadn't remembered remembering. But his subconscious must have caught it, and held it. In that moment, B knew he had won.
L Lawliet.
He, in his last moments, had remembered the name he had strove for so long to obtain. He had won,whether L knew it or not. It was a victory, none the less.
At the hands of the shinigami notebook died the only recorded possessor of natural shinigami eyes. The universe is a little bitch when it comes to irony.
Beyond Birthday was dead. L had been to later to save him, like he been too late to save A, the same way he would be too late to save Naomi Misora. The same way he'd be to late to save himself.
But B had died happy, unlike the other three. He'd died knowing A was on the other side, and, to a certain extent, had been avenged.