How I Met Your Mother does not belong to me.
It was his fault. Barney didn't own up to his mistakes often, but he knew that this was his fault. This was huge, this was stupidly huge, and he was the reason for it. So he sat quietly, and offered all he could, and paid for his mistake. Every night. Because that's what bros do.
Barney had been the one to find that girl that night. The stupid cheesy line of "Haaaaaaaave you met Ted?" was thrown out and she glided in like a boat to a dock. It had been so easy, just like the countless other times it had worked. Only, this time was a disaster, one that Barney would never speak of to anyone ever. Because not only could it ruin him, it could ruin Ted.
And that was one thing Barney could never allow.
Barney sat in his apartment, lights off, waiting. Ever since that night he had refused to take a date home. True, Ted had said it was alright for him to do so now and then. But something deep in Barney's heart told him that he just couldn't. He couldn't drop Ted like that. Because even one night of slacking off could get himself, or Ted, or someone else killed. He'll never forget that night, it had been burned into his eyes and soul.
Barney had found Ted first; bleeding, shaking, sobbing for someone to help him. The bitch hadn't finished the job. She had left him there to die, and suffer, and leave everyone wondering. But Barney had come in time to find him, to hold his hand, to remember the bedtime stories his brother had told him. Barney had been the one to save Ted. Barney had given Ted the gift of living death.
Barney had sent Ted to bed with a vampire.
The sex had been great, Ted had told him a few days later while they had a smoke under the moon. She really knew what she was doing. But right at the end she bit him, killing the mood and almost killing Ted. She had drained him of every drop of blood, smirked, and vanished just as Barney came thundering in. The noise had frightened his own date away, effectively cockblocking him. But seeing Ted draped across the bed, naked, neck bleeding, gasping for air…
Barney had always loved myths about the creatures of the night. Werewolves, vampires, you name it he loved it. He knew the signs when he saw it, though he always thought they were just that; a story. He saw the punctures on Ted's neck. He saw the paleness of Ted's skin. His twelve year old brain kicked in and knew that it was a vampire. Normal people, normal adults, would not have thought such things. Barney was the furthest thing from normal that there could be. Even counting Ted right now.
Barney had found a pair of scissors in the drawer of the night stand. He had cut a small slice into the inside of his elbow, and offered it to Ted. Ted was so far gone he didn't remember a single second of it. But the blood had done its magic; dripping from the thin arm into his mouth, down his chin, until the taste drove him mad and he latched onto his friend's arm, sucking in the life-giving wine. With a gentle tug, Barney pulled Ted away once color started to come back to his face, bending his elbow and stopping the flow, letting it scab over as Ted passed out.
Barney had done this to him. Barney had turned Ted into a vampire.