I have always believed that the multiverse theory, a universe that does not consist of just one universe but of many more, is a scenario we only see in science fiction movies. That it's just a philosophical thought and cannot be proven scientifically. Scientists may consider it as a possible scenario, but it's precisely what the name says: A theory. In other words, you may be proven wrong in the end.

But enough with the scientific stuff. I don't have enough knowledge of physics anyway. Let's take a look at what happened that night instead. Before everything that followed afterwards. The night I stopped questioning the existence of parallel worlds.

A chill air blew over my face. I had the feeling I was in an empty space along with some entity. Neither I saw nor heard it. I could only feel its presence. Almost like a ghost. I opened my eyes. In front of me, there was a huge grey dome, like those we often see in planetariums. There was no ground, but my body felt like it lay somewhere soft like a pillow. Most importantly, the dome wasn't bare. It was adorned with thousands or even millions of balls of various sizes. Some were huge. Others were smaller. And some others were tiny like ants. In the balls could be seen blurry images reminiscent of space and planets. Nothing could be heard. Absolutely nothing. A deafening silence spread in this area. My breath sounded like a roar and I could even hear my own heartbeat. It was that quiet...

Of course, I didn't omit to wonder where was I, and what kind of place this was. I didn't even know if I was awake or asleep. This area definitely seemed utopian like a scene from a Salvador Dali painting. There was no way I could be awake. And yet... This location just seemed real.

Then a humanoid creature appeared in front of me. To be precise, it definitely looked human. It had a female morph. Her hair was long and wavy with a light brown colour. She wore a long white tunic and thus looked like a resident of ancient Greece. She floated in the air. She was bright like an angel, although she wasn't wearing a halo. She was looking at me with a serious, yet filled with tenderness look. I felt slight awe when beheld her.

"Marina..." she said in a deep voice. I didn't respond.

"Do you know who I might be?"

I nodded showing her my lack of knowledge. "I am Nyx."

"The goddess of the night? From our mythology?"

"Exactly"

"How do you know what my name is?"

"I do know it. From your sister Helen. Do you remember two years ago when she showed you a blue marker she got as a Christmas present? She told you it is magic, but you did not believe her words."

"Of course, I do. It can't be easily forgotten."

"I sent it to her. When she said she would tell the spirit to repair some things, she was actually referring to me."

I remember everything that happened two years ago when I travelled with the marker and became a member of the Japanese police for a while. I also remembered Helen's words when she said she would send the "spirit" to fix it, as Nyx correctly said. But for some reason, I thought she was a man.

"My sister was referring to a woman by the term spirit," I laughed awkwardly.

"Anyhow..." The goddess seemed to be annoyed I confused her gender.

"Since the subject is relevant, tell me goddess Nyx. What kind of place is this? And why am I here?"

She approached me without stepping on the soft floor on which I was standing.

"I suppose you might be knowing about the mythology of your country. Since you know me, you know its basic features too."

"Indeed I know! At the beginning of the world, there was Chaos which he's your father. Gaia, Erebus and Tartarus are your siblings while Erebus is also the father of your children. That is, Aether, Hemera, Hypnos, Thanatos and Charon."

"Anything else you might be remembering?" she asked.

"Um... I only know your family tree." I chuckled. Though I shouldn't since I was in front of a goddess.

"Well, I do not need to get into details. That is all I wanted to ask you."

"As you already know, the cosmos was created by my father. And when I say "cosmos" I am not only referring to the planet Earth but the universe in all its glory. Humans think the universe is just one when in reality there are billions of universes. The balls you see floating in this area are remnants of when Chaos made the cosmos. Each ball is a different version of the universe, and since there are a lot of universes, it's obviously called the multiverse.

»Though I do not mean there's an authentic universe. What ordinary mortals think of as an authentic universe does not exist in reality. They just feel familiar with this world and can't imagine another one. The sun, the stars, the planets of your solar system, the Earth, all these make you feel intimate. Because you guys grew up in this world, and mere knowing yours. And it does not matter which universe you are in. The inhabitants of the other planets feel the same way about their worlds."

"So... These balls are different universes," I concluded.

"Exactly. But please don't interrupt." The goddess said calmly.

"You see, the marker was made by me. And the truth is, I didn't give it as a gift to your sister. It just happened to fall on Earth, —due to am negligent— and it was New Year's Eve, so it seemed it was a gift from Santa Claus. So, I remembered I hadn't conquered it, and thus was afraid it might fall to the wrong person. But when I arrived on Earth, the effect of my carelessness had already been done. Helen played with it a couple of times and found out she liked it. She was a good girl the whole year anyway, so I thought she deserved it."

»I suppose you understand a mortal cannot see supernatural matters for games, nor can they control the world on their own. I initially made the marker to serve me in my work. You see, apart from the night, I also regulate time. Past, present and future. Time doesn't exist in reality. Time is something humans have made to put things in order. Something that would help them do their duties and responsibilities. What you, common mortals consider as past, present and future do happen at the same time, but in other dimensions instead of yours.

»For instance, the World War IImarked humanity. It may not take place in your own universe anymore, but it does in another. Within the millions of universes that exist. Right now, it is taking place in one of these worlds. Yet, in another universe, humans may not exist as a species, and thus none of these catastrophic events occurs, nor do the civilizations. Absolutely nothing. No sign of mortal existence. As for time travel, it can be considered dangerous for a mortal as they travel through the speed of light. It's around three hundred thousand kilometres per hour. And the human body cannot survive at such a speed. But that doesn't mean you died during your journey. Neither your sister did. Due to this nonsense of mine, I had to slow down the speed."

"So... Why am I here?"

"Right now, you're sleeping. Your physical body and brain are asleep, but your stellar body has escaped your universe. You're not dreaming, but you're not awake either. You're stuck in a state between sleeping and awakening. This is why you're in this area, something that few mortals achieve. The universes in a nutshell are the worlds of dreams. This is where souls come when they die and when they dream. They just don't see the balls. A mortal can obviously not see with the unaided eye, but with the eyes of their soul." she explained.

"The same goes for you. You don't see these worlds with your vision but with your heart." she smiled.

"And what's the conclusion of all this?"

"That the adventure you experienced two years ago in your own world, is just a fraction of the universe. Listen. The events with the deadly notebook exist in every dimension. There are just small or huge differences between each of them. From the personality of the shareholders to the evolution of the case. Do you understand now?"

I didn't comment on anything she said. I just stared in awe and admiration at this utopian place. Things I didn't even believe exist, and now I was given the opportunity to see. Not only these parallel worlds but also goddess Nyx. The one I thought was a phantom until now.

What to comment first about this place? The balls and their strange colourations? That there's no time? That there's something completely different in the other worlds? And if that difference exists, then... There's another Light? Another L? Another Matsuda? A different version of them? And what version do I have in the other universes? I may or may not exist. I may never be brought to this world.

"Oh, dear girl. You seem worried. Have you been startled by this situation?" The goddess asked.

"I'm not. It's just... I experience it for the first time and it seems... Odd. Like there's no authentic universe and that all the matter in our world is just pieces of billions of universes. I mean... What exists in the other universes? What kind of matter? I'm pretty curious right now."

"I understand. It's indeed the first experience for a common mortal. Unfortunately, I can't tell you what exists in the universes, as I cannot be certain either. I may be a goddess, but I'm aware of little things about my father's creation. He's old now and can't do many things due to senility. You see, my siblings said I should look after him."

"How old is he if I may ask?"

"Do you know how old is the universe?"

I nodded my head in disagreement.

"13.7 billion years. My father's a little older than the universe. He's twice as old. You see, he's permanently in bed. He sleeps much more than usual, and he sometimes calls me Leonidas or Epaminondas. He even calls me Patroclus. He thinks we're still living in ancient Greece. I can't blame him though..."

Maybe he has dementia or Alzheimer's... I thought.

"I understand what you mean."

"Yes... I do everything I can to take care of him. That's what happens with elderly people. He's staying here since I have nowhere else to take him."

"What do you mean?"

"Oh, I forgot to tell you. The multiverse area is our home. I dwell here with my father. We're gods and we live hundreds of years. Well... We're bored with our lives!"

For a while, there was silence between us.

"So in other words... L, Light, Misa and everyone I met belong to my own world? And if so, to what extent do they correspond to reality?"

"If you wouldn't mind explaining," she said.

"You said that in every universe people's personality changes a little, even the events that take place. Could it be there's another version of myself, my sister's, my parent's or the people I met during the case? If that's the case, are these our true selves?"

"There's no true or false in the universes. The inhabitants of a universe may think that a person is rude for instance. For them, it's their true self. In another one, they may be kind and good-hearted. This rule applies to every universe. It doesn't matter how people around you see you. What matters is that within the billions of universes there's a different version of yourself that you don't know or will ever find out."

»As for you and the Kira case, yes there're many versions of yourself and the people close to you. I would show you what your personality is like in the other universes, but a time paradox will be created."

"A time what?"

"A time paradox. It means the universes will be mixed with each other. Events will be forgotten or added and thus, end up confusing yourself. You may even disappear. In other words, chaos will be created in terms of your existence. That's why I never show the alternative selves to people who have out-of-body experiences. Just like you."

I listened to her words carefully. It felt like she was a teacher explaining her lesson. Although I was a little curious to know different I am compared to the other Marinas out there.

"Can I least see how the shareholders of the case are?"

"Naturally! But we better be quick. Time has passed and you'll have to wake up. Is eight o'clock."

"But it's Saturday! I mean... I am only ten minutes here."

"It's the world of gods. Don't be confused. In your own world, it's Friday and you have to go to school. It may only have been ten minutes here, but on Earth have passed ten hours. Though even if it wasn't a school day, you may not stay longer, because your stellar body wouldn't return to the physical one and thus, fall into a coma."

"Oh, those are just details," I giggled "what do we have to lose? You're a goddess after all. You can do whatever you want. I suppose you can even run with eighty hundred kilometres per hour."

"I'll try, dear..."

And so, she took my hand helping me stand in the void without falling. The luminous balls seemed now bigger than before. As if their shape was changing. But as Nyx explained, it happens often when someone is about to enter the universes. Nothing inside of them changes. That's just the feeling.

A huge luminous ball made its spectacular appearance. I could see the planets and stars inside of it. And yet it wasn't my own world. Nyx said she'll hug me because we were about to travel with the speed of light. If she gave me some dose of her divine power, I would be able to survive.

She held me in her arms, and so did I while watching her right hand opening a hole in the ball. A dazzling gleam appeared. I closed tightly my eyes and left her divine power passing through my skin. It was the moment I would see what the cosmos is really like, and what extraterrestrial matter exists in the other parallel dimensions.

*The multiverse theory was first formulated in the 1950s by the American physicist Hugh Everett. It's based on very solid mathematical foundations and that's why it's difficult to prove. However, it's still a new idea for the scientific community, up to this day.

This fic is a sequel which means you'll have to read the first story in order to understand the events. But I suggest you wait because the first story is still under correction. You see I wrote it when I was like in the 9th grade. Obviously, someone's writing at this age is still developing. :D