"It's not possible"
In the castle of dreams, seating on a chair behind a white table, Echidna spoke. It was to Subaru, who had walked away and wanted to leave.
"What do you mean it's not possible?! If you're the one who brought me here, then it's only reasonable to think that you're also the one who can send me back, no?"
Echidna took a sip from the cup of tea in her hands, with her ever curious smile on her face as she observed Subaru.
"Stop ignoring me!"
Subaru would've slammed his fists into the table had it not been for his recent experiences with some of those witches. Though his angered expression was still on his face.
"Or is it not about 'capability'? What do I have to do for you to let me leave?"
Echidna sighed at the impatient Subaru and warped her hands around the cup of tea as she closed her eyes.
"It's reasonable to assume that, and that would've been normally the case. However, even if you were to pay a compensation I still wouldn't be able to send you back."
She opened her eyes and stared directly at Subaru's.
"Because Natsuki Subaru has died and his body is now a corpse incapable of hosting a soul."
"…"
"Don't you have anything to say?"
"That's not possible, if that were the case then…"
"Then?"
Her curious smile that had disappeared from her face moments ago was back on now. It was an uncanny smile that resonated with the sinister stare she gave through her pitch black eyes. Subaru didn't know what it was about her smile that made it uncanny or her eyes that made him uncomfortable when they were on him. In fact, if you were to show him a picture of her outside of this situation, he'd find them pretty normal. It was only in her presence that he noticed these things.
"Then… I can't tell you that. You or anyone else. However, it's an undeniable truth that I cannot have died. In the first place, if I were dead then how am I even here talking to you?"
Subaru sat in his seat behind the table across Echidna. He wanted nothing more than to leave, but it seemed that the witch wanted to play games. And if that was what she wanted, then he had no choice but to obligate.
"As I said before at the beginning, it's not your physical body that is here but a manifestation of your mind itself."
"…"
Seeing the silent Subaru, Echidna continued.
"For some reason, since you entered my tomb and came here your physical body has died. Your soul has left it too. But because it happened whilst you were here, your mind and consciousness remained in my castle without fading away. That doesn't mean you can go back to the real world though."
Through steady eyes, Echidna watched the frozen Subaru. It was not just that realizing revelation's graveness made him not know what to say.
"What you say, I simply cannot accept it."
That would mean the mechanism of Return by Death had failed to act on its purpose. Even if his mind was here, the fact that his physical body had died and his soul had left it would mean he truly died without going back. He couldn't even fathom how he could cling to existence without a soul. That was the usual trope in those kind of stories, your body is a vessel and your soul is what you truly are, but the existence of his mind isolated from his soul was a matter for another time.
"I can't accept it but, you're not the the sort of person to lie. That's the impression I got."
"Is that so, even after you got so angry, how flattering."
"Do you rather it to be flattening?"
At Subaru's joke Echidna raised an eyebrow.
"Don't give me that look, it's disturbing! Now that I think about it, that was the worst out of my unsuccessful attempts at humor, please forget it!"
But ultimately that was right. Echidna wasn't the sort of person who'd outright lie, and she didn't really have any reason to do so. If she wanted Subaru to stay her so much she could restore to forceful methods. She probably was the type who'd go first kill your body then come back and tell you she can't send you back because you've died. Regardless of what or who had caused Subaru's death, it didn't change the fact that Return by Death could not be relied on anymore because of the special circumstances during which death had occurred.
"So I'm pretty much stuck here… I would've expected to be more panicked, but for some reason I'm calm as ever like I've got the news that there won't be school tomorrow."
"…"
"Isn't there any way for me to go back? Like some forbidden magic that requires you to sell your soul or something?"
Echidna took another sip from her tea as she pondered.
"Forbidden magic … ? There are some spells that can bring a dead person back to life. 'The sacrament of the immortal king', it's said long ago a witch whose name is forgotten now devised it."
Hope glimmered within Subaru's eyes, but before he could get himself carried ever he shut it down.
"But naturally there is a catch, right?"
I could never get off so easily, that's what he thought.
"Once the person is revived and their soul dwells in their body again, there isn't much of their original self left there because of the process that happens when the spell is cast."
"So you mean I'll get turned to a zombie? But even if it isn't the apocalyptic kind, that's not very helpful."
"Though, that's not the case for you. Because a manifestation of your mind is here, the corrupted self that resides within your body when the spell is cast can be overwritten, removing the side effect if a magician skilled in water magic does it."
Well that was good news at last.
"So we just need a powerful spell caster, well Roswaal is the most powerful mage of the kingdom. Wait no, I once heard him say he can't use healing magic, that's water magic right? So he is out of the equation… well there is you, can't you do it?"
"When I was alive, yes. But now that I've died, even if I survive in this from I have no authority over the outside world"
"…"
"Unless someone were to complete the trials, then I could cast the spell."
"Trials?"
'Trial', that wasn't a word he had a fond memory of. It was the same word that disgusting man, Archbishop of Sloth Petelgeuse Romanee-Conti had said too many times, when he attempted to corner Emilia and have her act as a vessel for when he resurrected the witch. If that was what these trials were like too, then-
"Don't look so troubled. It's only a test that involves one's past, present and future. If the trials are complete then the seal which prevents me from accessing the real world is disabled."
"Echidna, I don't know what exactly you mean by that, but can I try to complete them? I-"
"A generous offer but I'll have to shut it down. Because you've entered the castle of dreams, you can't participate the trials through here. You'll have to return to the real word and reenter the tomb once again. Furthermore, you don't possess the qualifications. Only half-bloods can do it."
Most of the people he knew were full humans or demi-humans. Maybe there were some in the sanctuary but Subaru doubted they'd go through the trouble for him; However-
"Emilia… she can do it. But how would she know that in the first place?"
She was probably dead worried about him and where he was. She'll probably reunite with Roswaal and ask him for help, and then when they found his corpse in the tomb completing some trials would be the last thing in her mind. There was also the matter of Otto whom Subaru had promised an audience with Roswaal.
"If one of your companions who possesses the qualifications enters the tomb, you can inform them of the situation. Though I'd rather you don't mention or talk about me to them."
"Really? That's relief. It's solved then. I'll just have to spend a few hours with you until Emilia comes here… You're pretty reliable huh?"
Subaru leaned forward and laid his head on the table. A few hours… wow. How much time am I going to spend talking to a witch?! Though she was someone interesting to talk to, Subaru was the kind of person who slept through most of his history class. Unless it was something directly related to him he'd rather just sleep.
"But I can't do that with this weird blue sky and its clouds and that soothing breeze."
Echidna pouted and made a expression of sadness with her eyes closed, a shallow one. Not that Subaru noticed that.
"You wound my heart, is the idea of spending some time with me that undesirable to you? If you want, I can have you meet the other witches to spend your time…"
"No thank you!"
He'd rather not awaken a monster from her sleep, or get shredded into pieces because he felt a little guilty, or get lectured about safety and stuff like that by a blonde loli-witch. Not to mention the other two who he hadn't seen and didn't know what they were capable of.
"Man I wish there were some games we could play…"
"Games?"
"Not probably the kind of games you'd think of, the physical ones. I'm talking about the games from my world. But putting it that way might make create some misunderstandings."
My world, Subaru thought that from Echidna's perspective who was of a different time, that word meant the current time. After all, the world had changed a lot through 400 years. There wasn't a cult roaming it back then, and witches like Echidna weren't long forgotten like now, the witch of envy hadn't destroyed the half of the world and the kingdom of Lugunica wasn't the dragon kingdom of Lugunica. Royals were alive too. It could be said with no doubt that the current generation and Echidna's generation inhabited two different worlds in a sense. But that wasn't what Subaru meant when he said the words 'my world'.
"No, not my world. My hometown. In that place, there are these simulation of reality you can observe through some special windows. And there is a person or thing there that you can control to interact with that world. My people call them 'games'."
Echidna looked at the sky and leaned her face on her hand that was resting on the table as she pondered.
"How curious…"
"What is that?"
Subaru asked Echidna who had just put a book on the table. It was small enough to fit in his hands if he opened them completely. White, with no title or a picture on its cover, reminding him of the gospel Petelgeuse cared so much about. Though it had a different kind of feeling to it.
"Within this book exists all that there has been, there will be and there could and can be. Pulling this in the outside world might've not been this easy, but not here, since this citadel is over my complete control."
Suddenly, pushing his hands against the table, Subaru sprang upwards from his seat and took a few steps back.
"Woah woah WOAH! What is happening?!"
All of a sudden, a strong wind blew in the calm and stand-still citadel. The blue and steady sky darkened, no. It split into nine, each a color and tone of its own. One full of stars, one covered by black clouds and one filled with white ones. In one thunder shone and in one rain ruled. In one there was sound of rivers and springers, and in one screams of terror within the battle field. In the clash of the rain and snow, Subaru and Echidna stood in the center of it all.
"A legend of the past,-"
All-consuming shadows were everywhere, swallowing everything in their way.
"Or one of the future?"
An army rushed towards a walled city as a black-haired boy led them, crushing every soldier that stood in their way.
"A present that could never be,"
Wearing uniforms, Garfiel and Otto were running towards a building that looked like a school with sandwiches in their mouths.
"Or a story that might be about to happen?"
In a walled city, people were screaming and trying to run as waves of water consumed towards them.
"What is the story that Natsuki Subaru the human and Echidna the witch will enter and start their adventure in?"