Hayato's scream slowly faded, replaced by the quiet sound of futuristic traffic and the hiss of anti-gravity vehicles floating above the road.
He stood in the middle of a clean sidewalk, surrounded by curved architecture and holographic advertisements projecting women in mecha combat suits. Infinite Stratos.
A world where mechanized combat suits called IS could only be piloted by women—with one male exception.
"SERA," Hayato called, his voice tense. "Analysis. Way back."
SERA appeared as a small hologram beside him, her virtual face showing a serious expression. "Analyzing dimensional coordinates… Searching for a return path to the DxD/To Love-Ru hybrid universe…"
Her light fingers danced over an invisible keyboard. "Not found. The dimensional jump performed by Lala's device is random and leaves no stable resonance trace. We are stranded."
"Contact Zelretch."
"Attempting to open Kaleidoscope communication channel…" SERA fell silent for a moment.
"No response. But based on previous behavioral patterns, it's highly likely he is observing and… laughing."
"Of course," grumbled Hayato. He took a deep breath, trying to calm himself. Panic wouldn't solve the problem.
"Alright. First priority: temporary accommodation. We need a place to stay. And possibly fake identities for this world."
"That can be arranged," said SERA. "But there's a major problem: Tabane Shinonono."
"The crazy genius scientist who created the IS and has access to almost every system in the world?"
"Exactly. She has backdoors to almost every government database, global biometric system, even deleted file histories. Creating a fake ID with a history dating back years? Detection probability 98%."
Hayato sighed. "Then?"
"We still need ID for practical things—renting a room, buying goods. I can create ones good enough to pass ordinary systems, but not Tabane's eyes. The risk is, she might become curious and track us. But there's an upside: based on this world's timeline, Ichika Orimura just graduated middle school. Major IS Academy events haven't started yet. So Tabane's attention might not be fully focused."
"Great," Hayato muttered sarcastically. "So we can hide under the radar of a genius who might be idly monitoring all anomalous data."
"In short: yes."
Hayato looked around. The sun was beginning to tilt west. "Alright. First step: get communications. I need a local smartphone."
They walked along the clean streets. Soon, they found a futuristic electronics store with holographic displays showing various phone models.
The store clerk—a young woman in minimalist uniform—greeted them with a professional smile.
Hayato chose the latest model with high specs, paying with his American Express Black Card. The card worked without issue—the inter-world financial system, apparently, had been "tweaked" by SERA to remain valid. The clerk was impressed, serving them with more respect.
With a new smartphone in hand, the next step: accommodation. Hayato looked for a good hotel—he needed comfort and time to think. He found a star-rated hotel with a grand lobby, floor-to-ceiling glass walls, and soft lighting.
At the reception, a man in a neat suit greeted him. "Good evening, Sir. How may I help you?"
"I need a room for three days. The best one."
"Certainly. May I see your ID?"
Hayato took out the "identity card" SERA had just manifested from his inventory—a plastic card with his photo and fake data. The receptionist scanned it, and the machine beeped green. It seemed to pass the basic check.
"Suite on the 5th floor, room number 70. Here is your key card. The total bill…"
Hayato swiped his Black Card again. The transaction went smoothly.
"Thank you, Sir. Enjoy your stay."
---
The suite was spacious and luxurious. A king-size bed, leather sofa, large work desk, and a glass wall facing the cityscape beginning to light up with night lamps. Hayato threw himself onto the bed, feeling a fatigue more mental than physical.
"Goodness…" he murmured. "I miss Lala and Lilith."
SERA appeared beside the bed, her hologram glowing softly. "Relax, Host. There must be a way. Time flows differently here. My estimate: 1 hour in our home world equals 2 weeks in Infinite Stratos. So we have time to find a solution without being too rushed."
"That's a long time," Hayato complained. "They'll be worried."
"They are strong. Lilith is a Servant, Lala is an alien princess with a bag full of devices. They'll be fine."
SERA paused for a moment. "While we are here, this might be a good opportunity to give you… a lesson."
"A lesson?"
"About the multiverse. You need to understand where we are, to know how to get back."
SERA raised her hand. Suddenly, the lights in the room dimmed, and a large hologram began to fill the room. Not just a flat screen, but an immersive three-dimensional projection. Hayato felt as if he were floating in space.
"Look," SERA's voice echoed, yet softly. "This is our solar system: Sun, Mercury, Venus, Earth, Mars, and so on. All these planets are in one system, orbiting the same star."
The image zoomed out. The sun shrank into a small point among billions of other stars in the Milky Way galaxy. "This is a galaxy. Distances between stars are measured in light-years. For human civilization, this is an almost unreachable scale."
Then, the image changed again. No longer stars and nebulae, but… layers.
Like transparent glass sheets stacked, each containing images of different worlds: one showing a blue sky with flying mechas (IS), another showing eternal snow and giant crystal trees (Lostbelt), another a sea of stars and floating islands (Teyvat), then darkness moving like liquid (Abyss), and a shapeless expanse with floating fragments of worlds (Sea of Quanta).
"This is the multiverse," SERA explained. "A non-linear structure consisting of self-contained reality units, called World Layers. Each world has its own laws of physics, magic, and fate. Some are interconnected by structures like the 'Tree of Time', 'Akasha', or 'Irminsul'. Others… are just anomalies adrift in the Sea of Quanta."
Hayato was silent, absorbing the breathtaking and terrifying sight.
"A galaxy is about distance in space," SERA continued. "But worlds like IS and DxD are not just separated by distance. They are separated by the very concept of reality. You could spend thousands of years traversing one galaxy, but jump to another world in an instant—if you have access to the right conceptual pathways."
"For humans, a galaxy is the highest limit. But for outer entities… the multiverse is just gaps between shadows."
Hayato raised his hand, as if wanting to touch the projected world fragments. "What about… Outer Gods? How can they penetrate all worlds?"
SERA was silent for a moment. The images around them changed, showing incomprehensible silhouettes—forms bending against logic, eyes in the darkness, something whose mere presence felt threatening.
"Outer Gods do not 'walk' between worlds," SERA answered, her voice lower, almost whispering.
"They flow between the 'logical errors' of reality itself. They do not know space or time. They are not bound by laws of magic or science. They… exist because of the very absurdity."
"When you think they 'appear', they have already existed even before the concept of 'time' was created. Inter-world travel for them… is just like a human turning pages of a book. They can choose which page to read, or they can tear it."
Hayato clenched his fist, a feeling of helplessness creeping over him. "Then… what can I do if they appear before me? What use is the Arc of Embodiment if they can rewrite everything so easily?"
SERA looked at him, her holographic expression appearing almost… affectionate. "Your Arc of Embodiment is not a weapon to fight them head-on. But it is a tool to rewrite the framework of reality where they can touch you."
"As long as your imagination and will can shape reality, even formless entities can be forced to have 'limits' within the space you create. You are not just a protector of one world, Hayato. You are… the Pen of worlds that wish to survive."
Those words echoed in the room filled with cosmic projections. Hayato stared at the world fragments spinning around him—beauty, destruction, strangeness. He felt so small.
"SERA," he said quietly. "Forget about Outer Gods for now. Even thinking about them makes my existence feel shaky. Switch to something a little more… comprehensible. What's the difference between the Alien God from Lostbelt and Outer Gods? Are they the same?"
The images changed. Now displayed was a giant crystal tree emitting roots into the ground of a snowy world, and a vague figure with an inhuman crown.
"Alien God," SERA explained, "is an entity that manifests within a specific world's system—in this case, the Nasuverse, specifically Lostbelt—through the mechanism of 'Foreign God'. It implants itself as the root of a new reality through Fantasy Trees. Its goal is to replace existing civilization and history, not erase existence itself. It still operates within the framework of the world's concepts, albeit as a systemic invader."
The image changed again, showing a giant octopus-like being with wings sleeping in an underwater city, and a formless darkness older than the stars.
"Outer Gods, like those from Cthulhu mythos, are primordial cosmic entities existing outside space-time. They are unaffected by human logic or any laws of nature. Their power is absolute, cannot be defeated by physical beings because they are multiversal in scale and are inconsistencies of reality itself."
"Inter-world travel for an Alien God is like colonization with ships and roots. For an Outer God… it's like a dream they can turn into reality or cancel at will."
"Alien Gods can be explained, limited, and defeated through the rules of the world they enter. Outer Gods… cannot be 'defeated'. They can only be out-logic-ed by concepts surpassing the limits of human imagination."
SERA looked at Hayato. "And that is the role you might have to take, Hayato. Not as a hero wielding a sword, but as a writer holding the pen."
The holographic projections slowly faded. The room lights returned softly. Hayato was still sitting on the edge of the bed, looking out the window at the futuristic city glittering in the night. His mind was filled with the cosmic scale just presented to him.
He let out a long sigh, then lay back down, his head sinking into the soft pillow. "Truly… it's all insane. I hope… I could live peacefully. But it feels impossible after knowing all this."
SERA, still beside him, gave a small smile—a virtual expression full of understanding. "Take it slowly, Hayato. Your journey is still long. And you are not alone."
Hayato closed his eyes, exhaustion finally attacking. "Goodnight, SERA."
"Goodnight, Host. Sweet dreams… even if they might be about the multiverse."
Outside the window, the city of Infinite Stratos continued to pulse with life and technology. But in the luxurious hotel room, Hayato Hayama fell asleep with thoughts far beyond the ceiling of his room—beyond even the boundaries of the world where he was stranded.
And somewhere between the layers of reality, Zelretch watched with a cup of tea in his hand, smiling with satisfaction. "The lesson has begun. Let's see how quickly our Anomaly learns."