・Characters & Others (End of Volume 1)
This section summarizes Volume 1.
It has no impact on the story.
You may skip it without issue.
★Characters (End of Volume 1)
・Kumakura Hayato 18 years old, summoned to another world, returned after three years.
・Shiraishi Yui Self-proclaimed 18 years old, exiled after being bitten by a Zombie.
・Hoshino Natsuki Second-year student at Kirioka Agricultural High School. Her parents were abandoned at the school gate.
People of Kirioka Agricultural High School
・Oomori Vice Principal Hayato’s trading partner. Middle-aged.
・Kobayashi Teacher The one who taught about vehicles. In his thirties.
・Mia Female dormitory roommate of Natsuki.
・Kurohara The oldest student from last year’s graduating class. 19 years old.
Former construction worker
・Onigawara President. Traded with Kumo Nō. Middle-aged man with a large tattoo on his neck.
・Ogura Managing Director. Middle-aged man with a severe expression.
・Yamashita Section Chief. Tall, broad-shouldered man, built like a rugby player.
・Ippei Classmate of Kurohara from middle school. Purple hair.
★ Origin of Hayato's name
Kuma (bear) = Physical ability comparable to a grizzly bear
Kura (warehouse) = Spatial storage (kura = building for safely storing household goods and merchandise)
Hayato = People mentioned in the Kojiki as Kumazoe, and in the Nihon Shoki as Kumaso. Bear-destroyers
(Used as a given name; pronounced "Hayato")
★ Hayato's abilities
Physical ability = Grizzly bear level
Sacred magic = Healing (can also remove zombie virus)
Spatial storage = 80 tatami mats, or 200 feet container
※ Spatial storage is equivalent to Hayato's estimate of about eight tatami mats' worth or ten 20-foot containers.
Counting alone does not divide the space into individual rooms.
20-foot container internal dimensions 33.2 cubic meters × 10 = 332 cubic meters?
Hayato was expected to be dataized, given that weight and cargo efficiency could be ignored.
★Reasons for gaining power after being transferred to another world (Hayato's speculation only)
The transfer device—imagined as an installation by a civilization far surpassing Earth, set up for environmental experiments and similar purposes.
Body enhancement was automatically applied by the device to enable the user to withstand transfer.
— Sacred magic involves genetic modification and nano-machine implantation when using the device.
— Spatial storage operates through an embedded terminal from a hypercivilization, converting objects into data. Capacity limits stem from the terminal's data storage. Living organisms cannot be stored due to safety protocols.
• Conversations with individuals from the other world are translated automatically via embedded terminals.
• The individuals from the other world do not use the devices themselves because such devices do not exist on Earth and because they lack understanding of the devices.
• The time between transfers opens due to the lack of oversight by the hypercivilization and to allow energy accumulation.
• The incident in which transfer participants were killed and the device became inoperable was due solely to device failure.
• The similarity of planetary environments between Earth and the other world results from terraforming by the hypercivilization.
• The similarity of cultures between Earth and the other world results from the transfer of materials and knowledge by transfer participants.
★ Contents of the spatial storage
• During activities in the other world
1. Wooden crate containing rye bread
2. Wooden crate containing rye bread
3. Wooden crate containing cheese, wooden crate containing dried meat, wooden crate containing dried fruit, salt bag
4. Water bucket (25 liters, 664 units)
5. Water bucket
6. Water bucket
7. One hundred spears, three hundred bows, three hundred bow racks, three hundred quivers, six thousand arrows.
8. One thousand forty oil lamps, plant oil (one month’s supply at eight hours of daily use).
9. Two hundred sixty four-person tents, one thousand forty blankets.
10. Hayato’s personal items
・At the end of volume one
1. Wooden crate containing rye bread (occupying two-thirds of space)
Wooden crate containing cheese, wooden crate containing dried meat, wooden crate containing dried fruit, salt bag (occupying one-third of space)
2. Six hundred sixty-four water buckets (occupied, ※ internal container volume ÷ water bucket size)
3. Barrel containing high-octane gasoline and empty barrel (replenished as needed. Maximum quantity matches water bucket count)
4. One hundred spears, three hundred bows, three hundred bow racks, three hundred quivers, four thousand arrows.
Three hundred thirty-seven oil lamps, plant oil (ten days’ supply at eight hours of daily use)
Forty-person tent and blanket set, various car supplies, various crop seeds
5 Pharmacy collection: ten-kilogram rice bag
Threshing machine, hulling machine, two single-pass rice mill, inverter generator, twenty-liter oil in two cans
6 Empty (empty water bucket)
7 Empty (used for vehicle access)
8 Yui’s personal items (home + allocation from Hayato)
9 Natsuki’s personal items (dormitory)
10 Hayato’s personal items (home + other world. Includes personal gear), Bicycle
(Spear tip = Damascus steel, armor metal = spring steel)
★ Collected items after return
• Supermarket
Cleaning supplies
• Home
Personal items
• Station
Bicycle
• Shutter Street Pharmacy
Medicines, nutritional supplements, hygiene supplies, support bandages, various protein powders, other items
• Auto supplies store
Many Batteries, Ratchet set, wrenches, three sets of summer and winter tires and wheels
• Home Center
Work gloves (nitrile-coated, washable, XL) – 12 pairs
Threshing machine, hulling machine, single-pass rice mill, inverter generator, 20L oil – 2 cans
※ Rated load: continuous operation 7.5 hours, 1.2–1.5 L/h, 2800 Wh
¼ load: continuous operation 18 hours, 0.6–0.8 L/h, 700 Wh
• Gas station
Premium gasoline (fuel stabilizer included)
• Kirioka Agricultural High School
Various plant seeds, 10 kg rice
Glock 19 (12 rounds remaining)
• Stored items in spatial storage
Personal belongings of Yui and Natsuki
• Medications
Pain relievers, eczema and dermatitis treatment ointments, fever and pain relievers, nasal medication, performance enhancement drugs, various vitamin supplements, fluoride tooth decay prevention tablets, etc.
• Nutritional supplements
Nutritional drinks (various), powdered milk, baby food, liver oil drops, powdered drinks (green tea, black tea, black vinegar, lemon tart cherry), etc.
• Hygiene supplies
Hair growth and regrowth agents, adult diapers, topical ointments, various hair care, body care, and skin care products, antibacterial spray, masks, toothpaste, toothbrush, dental floss, tissue paper, toilet paper, etc.
• Supports
Various supports for hands, feet, and waist
• Various protein supplements:
Cereal calorie bars (chocolate, white, strawberry flavor), jelly (mixed fruit flavor), powder (coffee, cocoa, caramel, vanilla, muscat, grapefruit flavor), tablets (lemon drop flavor)
• Other
Some expired topical ointments
★ Hayato's title in the other world
Asteria Imperial Army, Demon Lord Assault Reinforcement Battalion, Special Operations Lieutenant
• Reinforcement Battalion
A unit augmented in personnel and supplies beyond the standard battalion (600 personnel, majors and below).
Reinforcement Battalions consist of 800 to 1,200 personnel, including majors and below, enabling long-term independent operations.
• Special Operations ○○
Selected personnel following an atypical promotion path. (Treatment varies by nation.)
Targeted at individuals with high specialization, ability to carry out special missions, or exceptional skill in a specific field.
★ Chronology
Three years ago: Hayato is summoned to the other world.
Zombies emerge in large numbers across the world’s nations.
Two and a half years ago: Fuel supply from overseas ceases.
(Japan’s crude oil reserves: 100 days for the state, 90 days for private sector. Approximately 6 to 7 months’ worth.)
Two years ago: Looting spreads, and Japan can no longer maintain order.
(Background: multiple infrastructure failures, fuel supply restricted to emergency vehicles only.)
One year ago: civilization collapse
(Anarchy. Near-total shutdown of infrastructure and administrative services.)
Current: Hayato is being returned from the other world.
Two years have passed since the stabilizer was administered.
★Q&A
———
Q1. Is gasoline still okay?
A1. The nation added fuel stabilizer to extend storage duration (Episode 11).
Fuel stabilizer is an additive that suppresses oxidation, degradation, and fuel tank corrosion.
Ordinarily, gasoline becomes unusable within about six months due to oxidation and evaporation.
With fuel stabilizer, gasoline remains usable for one to two years. Doubling or tripling the dosage further slows degradation.
Raw materials for fuel stabilizer are BHT, BHA, and ethylenediamine derivatives—sourced domestically.
Production is handled by domestic chemical manufacturers (Asahi Chemical, Mitsubishi Chemical, Nissan Chemical, Tokyo Chemical Industry).
Typically three to five years. Up to six to seven years in ideal conditions.
Substitutes include phenolic compounds, amine compounds, and sulfur compounds.
All are domestically produced, with shelf lives of two to four years, three to five years, and two to three years, respectively.
Phenolic compounds — producible domestically by Mitsubishi Chemical, Asahi Chemical, and Nippon Catalytic Chemical.
Amine compounds — producible domestically by Tokyo Chemical Industry, Nissan Chemical, and Shin-Etsu Chemical.
Sulfur compounds — producible domestically by ENEOS and Nippon Steel.
Thus, Hayato will secure gasoline for the next year without fail.
——
Q2. Do non-humans become zombies?
A2. Non-humans may not be easily infected. Reasons follow.
— The virus has evolved to infect and replicate in specific animals.
Evolutionary mechanism of host specificity. The virus exhibits a high mutation rate during replication of its RNA/DNA, naturally selecting for structures that bind more easily to host cell receptors, thereby acquiring an optimized infection mechanism for specific animal species.
• Scientific basis = molecular biology, virology
• Specific example = influenza virus (different strains in birds, pigs, humans)
• The zombie virus evolved specifically for humans in another world.
• Human and other animals differ in intracellular environment (proteins, enzymes, immune mechanisms). Differences in receptor structure on cell surfaces and specificity of intracellular enzymes inhibit effective replication in non-human animals. Thus, the virus may not infect other animals efficiently.
• The virus retains infectivity for a limited time when attached to vegetables (example below)
https://www.asahi.com/articles/ASN496K3XN47PLBJ007.html
※ In the earliest phase, there was global dissemination using the mana that had accumulated on Earth.
———
★ Summary of Volume 1
Hayato Kumakura, a third-year high school student, was summoned to another world in February. He was enrolled in an army fighting the Demon King.
After transfer, he gained the physical strength of a grizzly bear, sacred magic, and spatial storage. Three years later, after the Demon King was defeated and he was no longer needed, he was sent back to Earth. Upon return, zombies had spread across the planet.
From Togakushi Municipal High School, he moved to a supermarket, then to his home. While searching for a bicycle, he encountered a girl claiming to be eighteen years old, standing under 150 cm tall, wearing middle school uniform, named Yui Shirai. She had been expelled from a shelter after being bitten by a zombie.
Hayato, considering whether living out his days as a solitary elder while concealing his power was wise, proposed to Yui that she become his collaborator in exchange for rescue.
Yui said the price was not worth it. When Hayato, imagining her as labor for chores, said "body," she replied that he had raised her好感度. So that was the way it worked. Hayato, who had never seen her at high school, after careful thought decided not to clarify the misunderstanding.
But if they stayed in Kirigakure City and someone who knew of her bite discovered her, Hayato would be subjected to the Japanese government's virus treatment drug, and Yui would be tested for immunity—both would be imprisoned for life. After discussion, they decided to leave Kirigakure City.
To safely move Yui, Hayato acquired a vehicle, but the Battery had failed. He traveled to Kirioka Agricultural High School, where survivors might be found who could teach adults how to repair it.
Hayato, having traded supplies for knowledge, repaired the vehicle and obtained seeds for crops.
On the fourth trade attempt, seeking textbooks, he witnessed a group attempting to seize Kirioka Agricultural High School using Zombies.
Hayato rescued Natsuki, a girl from the school he had previously interacted with, and escaped with her. He destroyed the group that had released the Zombies. Returning Natsuki to Yui, her好感度 had increased but then decreased—she was angry. (Punchline)