Disclaimer: I don't own Buffy the Vampire Slayer or Doctor Who. If I did, I would probably be creative enough to come up with a funnier disclaimer.
The First was infinite. As long as life had existed, so had evil, and as long as life continued, so would evil. So would the First. It was everywhere, in everything and everyone. It was at the root of every evil deed ever committed, ever contemplated. It wormed into the hearts of men and twisted them. It had directed history- manipulated dictators, maneuvered genocides, prompted wars.
And it had seen him.
“You’re not running,” it said, quirking its head to the side. “How strange. You’re so good at it.”
The Doctor leaned back casually against the door of the TARDIS. “Weeell, this nice hole you’re trying to open between dimensions is leaking out quite a bit of energy. It works as an excellent source of fuel for the TARDIS. Also, I was considering stopping your attempt to destroy the Earth.”
The First snorted doubtfully, pushing a lock of Buffy’s blond hair away from its face. “You think the Earth will be the only planet affected when I open the Hellmouth?” it asked. “You’re really underestimating how much damage I’m going to do. The effects will be felt everywhere… I’m destroying the balance between good and evil. That’s not something you localize.”
“No. It’s not,” said the Doctor. "But it won’t happen.”
The First smirked. “You obviously don’t understand what you’re dealing with.”
“Of course I do,” he said, affronted. “I recognize the First Evil when I see it! But being the first doesn’t make you invincible.”
“No,” it said sarcastically. “Being invincible makes me invincible. Evil can’t be destroyed- I’m always going to be here, as long as there’s life. That’s the beauty of creation: it’s always on my side. I can’t be ended. Even those who fight against me give me more power- their rage, their hatred, their potential to give in and do something bad. They make me eternal.”
“Eternal doesn’t mean unbeatable.”
“Who says it doesn’t? The Slayer isn’t powerful enough to stop me,” it said. “It was her resurrection that gave me this opportunity. No matter how much you try to help her, the events that have laid this path down make this between us. And she isn’t strong enough.”
“I think you’re underestimating just how much humans are capable of.”
“Or maybe you’ve just gotten biased over the years.” The First’s form shifted into that of a handsome man in his late thirties. It smiled flirtatiously at the Doctor. “You do tend to pick the best of us, Doc.”
The Doctor gazed at its stolen face regretfully. “I’m sorry, Jack. If it weren’t for me, this thing wouldn’t be able to steal your face.”
“Wow, Doctor, that’s harsh. Thing?” It grinned self-appreciatively. “I like to think of myself more as an omnipotent, everlasting being with an undeniable presence in history.”
“Omnipotence would imply infinite knowledge,” said the Doctor.
“Which you’re implying I don’t have?” it asked. It changed again, this time into a young woman with bleached blond hair wearing too much mascara. “But I do, Doctor.”
The Doctor tensed. “Stop it.”
“I can be anywhere in the universe I want, whenever I want. While I’m here with you, I’m whispering into the ear of a man in China who just bought a shotgun; he’s going to use it on his ex-wife. I’m helping alien terrorists rig up a series of bombs in Cardiff that could kill over a hundred people. I’m with the Sontaran fleet as they’re decimating another planet’s population.” It smiled. “I’m the Big Bad Wolf, Doctor. I see all, and all fear me.”
“Stop it,” the Doctor repeated. “Rose Tyler isn’t dead. You can’t steal her face.”
“But you brought me to the past, didn’t you Doctor?” it asked, Rose's eyes gazing into his. “You made me part of events. And then… we left. My part in the past is done. It’s like—those parts of my life died when that time went by. Like you killed me, bit by bit, when we traveled.”
The Doctor’s fists clenched. “You see her as dead because your perception is limited.”
The First shifted back to the Slayer’s form. “Man, can you go on about a single topic. You keep telling me that I’m not all-seeing and all-knowing, but, you know, I kinda am. I’ve seen everything that’s ever happened and know everything that’s happening now—”
“But you have no concept of things that could be,” said the Doctor. “You see no possibilities but your own success when there are a thousand different paths this battle could take. You underestimate your adversaries and overestimate yourself.
“You’re the First Evil, the root and product of every terrible thought. And you truly do exemplify the worst of the universe: you have incredible pride—the most deadly sin.”
The First snorted. “Blah, blah, blah. Are you done yet? I thought you said you were going to actually do something about my plans instead of just rambling on about how I can’t possibly succeed because I’m just too darned cool for my own good. And really, thanks for that nice description. I found it to be quite flattering. You only left out my clear complexion and bouncy hair- well, technically Buffy’s clear complexion and bouncy hair, but, once I’ve killed her, who’s gonna know the difference?”
The Doctor was silent for a moment. “She has more power than you give her credit for,” he said. Then he turned and pulled out his TARDIS key.
“So you are running,” said the First, smirking. “Wow. All that speechifying about how I can be stopped and you’re still giving up. Which is the smart choice, I admit, but it really does take away a certain something from your point.”
“What? No, I told you. The TARDIS needed refueling- this was just a pit stop,” said the Doctor. “I’m off to see a girl about a Scythe.”
A/N: When I saw the FFA for this pairing, I was really intrigued. I wasn't sure I could actually write the ideas that popped into my head, and I'm still not sure whether or not I pulled it off. I'd really like people to tell me what they thought, or areas where I screwed up, or just places they enjoyed.
Writing the First was very fun for me because it takes on aspects of others while still retaining its own basic personality, so if I could hear how it came across to others in the fic I'd be really happy.