A bit more serious than anything I've ever done. Started writing this weekend and didn't stop until I finished a few hours ago.
It may be a bit confusing, but I hope it's clear enough. I also made it a bit more mysterious. Is it too angsty? And I decided to have Kid name the girl Octavia, because oct=eight in Latin.
See what I did there?

Enjoy, everyone.

You're like the missile kind,
little kingdoms in your chest
I told you we'd make it, on for another
I told you we'd make it, on for all night (Put on all our best)

"Balls, balls, balls!" There was a distinct pitter-pattering of my blood as it hit the cobblestone. "Can't we just conversate?"

An average-sized figure had cornered me in an alleyway. "Just give me back the book. It's very important." My bottom lip jutted out.

"What happened to the thrill of the chase? You're no fun anymore, Noah." My pout turned into a smile when I handed over the book. He smiled a little, too, before it turned into a sneer. The book, still touching both of our hands, attached itself to me before eating me whole. "Too dangerous to let go, too valuable to get rid of. So complicated, ne?" was the last thing I heard before being engulfed by darkness.

This is how they will live on,
but we'd look better if we win
I told you we'd make it, on for another (Oh I've been getting calls now out here)
I told you we'd make it, on for another (On their mouths and chests)

All the layers of the Book of Eibon, they stripped me down. I forgot everything, including my name, memories, what I looked like, the people I knew; it left me without struggle. God knows how long I was stuck in it before another was captured. He looked human, but something about him was definitely not. There were three stripes on the side of his head, which was a strange choice in fashion, though I wasn't one to judge.

"Who are you?" I called to him. He looked at me suspiciously before answering.

"Death the Kid, who are you?" There was a pause. He raised his eyebrows.

"Aah, that's a good question. But I'm glad to meet you." My smile was genuine; I hadn't talked to anyone since I had awoken here. There was a strange floating thing with a sharp nose, but it looked to busy to be bothered with someone who can't even remember their name. Death the Kid moved a bit closer and held out his hand. "Nice to meet you, too."

I placed my hand in his, and he shook it. The contrast between our skin shocked me a bit. His skin was pale and flawless, while mine was a faded tan, which made our handshake look like Yin and Yang.

"How long have you been in this book?"

"I don't remember."

"How old are you?"

"I don't remember."

Death the Kid frowned at my answers. He brought his hand to his chin, and stood there in thought for a few moments. "Would you like a name?"

"I would love one."

"I'll call you Octavia."

Help this love before you leave,
Demonstrations lack caress
I want you to take you, call on for life (Thank you for creating souls...)
The longer we make this, got no way there (Children sleep with ticks)

"What is it like, out there?" The huge white space we were in was endless, and we just floated there. There was no sense of time or space, but it was an easy existance inside the book. Nothing could hurt us, we never grew hungry, and we didn't have to do anything. It grew boring, however, to just be suspended forever like that.

"It's dangerous, asymmetrical, unbalanced, and full of madness." He looked a little angry, but snapped out of it and continued. "You would probably like it better in here."

"No. It sounds beautiful," I said. "Despite the danger out there, at least there's something. Here, there's nothing."

Kid looked like he was about to answer, but he suddenly disappeared. I wrapped my arms around my knees and rested my chin on them, to wait until he returned. He hadn't come back before a large cloud of darkness enveloped the air around me. It was thick with some sort of evil, that my brain couldn't process.

"It's you, child. The one who allied themselves with madness."

"Madness? Isn't that bad?"

"Of course not, Pandora."

"My name is Octavia. Who are you?"

"So you do not remember? Perhaps you have been in the book too long. I am one of the great old ones, and that boy is a fragment of another old one. He is the fragment of Death."

"You know who I am?"

"I'll show you, child."

"No, thank you. I have no desire to learn about my past anymore. Not since I met Death the Kid." I smiled in the direction of the dark mass before it retreated.

"Very well. But you must know that everyone changes, under the influence of madness," it chuckled. I shivered slightly.

The Yukon keeps me up all night
Complication sees your best
Told you, I want it here longer for you (I've been getting calls out here)
I waited, I waited, it's late night, she's waiting at home (On their mouths and chest)

Death the Kid came back. He had bruises scattered on his pale skin, but he said it would go away in a matter of minutes. Don't worry, he said. It doesn't hurt, he said. My worry almost subsided before the darkness came back and devoured us both.

"I am not your ally, nor am I your anything..."

It covered Kid in darkness and drove him mad. Something changed in his eyes, that made his pupils dialate and his mouth curve upwards in a grin. All I could do was watch, as his being was stripped of its sanity. Five vertical lines appeared on his mouth, while a new wardrobe formed atop his sleeveless shirt.

"Death the Kid? Are you alright?" My worry was evident in my words. I moved closer, hoping to look him in the eye.

"Nothingness... the pinnacle of order," he mumbled. My hand touched his, but this time the contrast no longer baffled me. I felt that it belonged, both the darkness and light. Madness and courage were two sides of the same coin. My sanity would balance with his newly found madness, and we would blend like Yin and Yang.

We got love and hate, it's the only way
We got love and hate, it's the only way

"Kid, what will you do next?" Our fingers found themselves intertwining.

"I will seek 'nothingness,'" he replied. "Will you join me, Octavia?"

"Yes," was my only reply. He nodded.

I think it's almost crimes

A song echoed across the world we met in. I thought about who I was, and whether that person had an impact on another's life. I wondered whether I was good or evil. Whether my past mattered at all. I committed my new name to memory and wondered how we were going to attain "nothingness."

I think it's almost crimes

I hummed along with the echoes. They reverberated through my bones and I thought Kid could feel it too; maybe the vibrations were coming from the hummingbirds fluttering in my chest. His skin, bruised only moments ago, was healed and glowing in the light that was shining from up ahead.

I think it's almost crimes

There was nothing left, now. We knew, we both silently agreed, that on the other side of the door there was nothingness. I decided that my past didn't matter, and my future was nonexistant. Death the Kid and I were in front of the bright column. Our hands clasped together a little tighter, warming each other. He chuckled, a deep, dark chuckle. I looked up at him and he smiled back, a trace of sanity still left behind in his golden eyes.

I think it's almost time

We stepped into the light.