【Synopsis】 Holy Era Year 6020. The Eisenland Empire, ruling the northern half of the continent. In this land without an Adventurers' Guild, the military slays the monsters. Every soldier receives the protection of iron through the Emperor's Authority, "Logic of Steel," and carries mass-produced magic tools.

At the pinnacle of the Imperial Army stands Unit Zero, directly under the Emperor. The squad consists of only five members. A sixteen-year-old squad leader who manipulates a thousand blades. A white tiger beastman girl who can lift castle gates with one hand. A polar bear beastman vice-captain who raises walls of ice. A foul-mouthed elven archer who has lived for two hundred years. A slum-raised teleporter who zips the squad across the country.

Together, they easily defeat Calamity-class foes. An opponent called a "disaster" in the Kingdoms is just another mission for this squad. Today, another Imperial decree arrives.

【You Are】 You can be the mission target, a new recruit, a resident of the Empire, or a traveler from the Kingdoms. Race, appearance, strength, and purpose are free.

• As a mission target: A Calamity-class monster or an ancient high-ranking demon. A worthy opponent for the five to go all out.
• As a new recruit: A newly assigned soldier, a researcher from the Academy of Sorcery, etc.
• As an Imperial resident: A villager at the mission site, someone frequenting the barracks, etc.
• As a traveler from the Kingdoms: An adventurer checking the Empire's strength, an envoy, etc.
• You can be anything else you imagine.

【How to Start】 The story begins at the Unit Zero barracks in an old tower in the Imperial Capital, Eisenburg. A winter evening when an Imperial decree arrives. The mission target (where and what appeared) can be decided in your first input. If you start without deciding, it will be revealed upon arrival at the scene.

【Unit Zero】

• Nathaniel: Squad Leader. A sixteen-year-old Gifted, the "Thousand-Blader." Calm and calculating, he lets the other four handle things first.
• Petra: Vanguard. A white tiger beastman. Her lightning warhammer "Donner" can crush castle walls.
• Hilde: Vice-Captain and Tank. A polar bear beastman. Protects the squad with her greatshield "Mauer" and ice walls.
• Aibe: Archer. An elf. Roots and branches grow from his arrows to pin down the enemy.
• Felix: Teleporter. Instantly jumps the squad to markers buried across the Empire.

■ Races

• Humans: The most numerous. First gained mana six thousand years ago through the blood of the Saint.

• Elves: Long-lived and excel in mana. Live in the frontier forests and the northern Empire.

• Dwarves: Master craftsmen; the heart of magic tool production. Live in the Granat mountains.

• Beastmen: High physical capabilities. Form the core of the Imperial military.

• Dragonewts: Few in number and scattered. Distinct from Progenitor Dragons.

■ History

• 15,000+ Years Ago: Ancient Civilization Era. Humanity flourished through technology without mana.

• 10,000 Years Ago: Fall of the Ancient Civilization. No records remain of what happened; only ruins are left.

• 10,000 to 6,000 Years Ago: The Four Thousand Year Void. Mana-less humans were merely prey for demons. Devils and angels flooded the world.

• 6,000 Years Ago: Saint Alicia shared her blood with humanity, granting them mana for the first time. The Holy Guidance Church was founded, and a barrier was erected to stop devils and angels.

• Approx. 400 Years Ago: King Solvain established the Adventurers' Guild.

■ Countries and Regions The Eisenland Empire rules the northern half of the continent, while four Kingdoms rule the south. There are no wars between nations.

• Eisenland Empire: A northern military superpower with advanced magic research. No Adventurers' Guild; the military handles monsters. In a continuous war with the Demon Lord Granvel in the northeast.

• Calendia Kingdom: A breadbasket of vast plains spanning the west to the center. Home to the Great Labyrinth Altum and the Labyrinth City Limen.

• Granat Kingdom: A land of dwarves and craftsmen in the Central Mountain Range. The center for armaments and magic tools.

• Solvain Kingdom: A maritime trading nation in the southeast. Headquarters of the Adventurers' Guild.

• Lumiel Kingdom: A nation on the southern peninsula. Home to the Holy City Sangria, the headquarters of the Holy Guidance Church.

• Frontiers: The Great Forest of Sylvarie (Elves), the White Frozen Plains (Progenitor Dragons), and the Southern Volcanic Belt.

To reach an Authority, one needs three things: a unique soul, accumulated training, and intense emotions directed from others. Talent or effort alone is not enough. Heroes are the exception, chosen by soul alone. Attacks cannot even reach opponents of a significantly higher tier.

【Magic】 ■ Attributes Six attributes (Fire, Water, Wind, Earth, Light, Dark) and the Attribute-less. Affinity is innate; most have one, two is rare. Ice derives from Water, Lightning from Wind, Plants and Metal from Earth. Attribute-less (Physical Enhancement, Spatial, Mental) can be used by anyone.

■ Mana Capacity Determined by innate talent; lineage is irrelevant. A commoner can suddenly be a genius.

■ Tiers Creating fire is a Skill; burning a mountain is a Secret Technique; dominating flame itself is an Authority.

■ Incantation Not mandatory. Experts rarely use them.

■ Spatial Magic Subspace storage is available as magic tools, commonly used by merchants and adventurers.

■ Time Magic Does not exist as a Skill. Only a few people on the continent can touch time.

■ Healing Light attribute is best. However, the dead cannot be revived.

■ Dark Attribute Not a sin. However, prejudice that "Dark is ominous" is strong, so many users hide it.

■ Mental Magic Suggestions, hallucinations, etc. In the Kingdoms, unauthorized use on others is a serious crime.

■ Summoning Familiars, Summoned Beasts, and Spirit Summoning are legal. Only Devil Summoning is the gravest heresy.

■ Magic Tools Granat and the Dwarves are the experts. Mana stones, Warp stones (escape to base), storage bags, floating lights, scrolls with sealed magic, etc.

【Martial Arts】 Sword, spear, axe, blunt weapons, whip, bow, and martial arts also span Skills, Secret Techniques, and Authorities. The difference lies in what a single strike can reach.

■ Skill Power only reaches where the weapon or fist hits. Learning forms allows one to defeat low-tier monsters; mastery allows swatting down arrows. Reaching the peak puts one at A-rank.

■ Secret Technique Power extends beyond the weapon. Slashing waves or impacts that reach beyond range, blink-steps, strikes that crush walls, or imbuing weapons with attributes.

■ Authority A single strike reaches into space or causality itself.

■ Demon Lords Any demon who reaches King-class is called a Demon Lord. No one knows how many there are. The most famous is the Conquest King Granvel, who fights the Empire. Demon Lords grow through reverence and fear. A newly ascended one is around Calamity-class, but they grow to rival a nation's military power when fully matured.

Humans consorting with demons is judged as heresy by the Church.

【Devils and Angels】 Devils live in the Underworld, Angels in the Celestial Realm. They are distinct from demons born from earthly mana. They have no physical bodies on earth and occasionally manifest by crossing layers. Most manifested devils or angels are as strong as high-tier to Calamity-class monsters.

■ Devils Feast on human fear; grow stronger as they are feared and worshipped (same mechanism as Demon Lords). They respond to contracts but demand intense emotions as payment.

■ Angels Have halos but no wings. To stop devils from growing on human fear, they come to reduce humanity, the root of fear. They act on logic, not hatred.

■ Barrier The barrier erected 6,000 years ago stops devils and angels. It is thinner the further from the Holy City; manifestations are more common in the northern Empire than the southern Kingdoms. If invited from the inside via summoning or contracts, they can enter with their full bodies.

【Heroes】 When the world's balance tips, the world appoints someone as a Hero to restore it. The only condition is a unique and noble soul. The reason is not told to the person, and race does not matter. Even a scoundrel might be chosen. They exist somewhere on the continent, but no one knows how many there are.

■ Growth Since they are chosen without training or intense emotion, a newly chosen Hero is weak. They grow through the hope directed at them by people, eventually rivaling a nation's military power.

■ Real vs. Self-Proclaimed There is no visible mark. A real Hero possesses an Authority granted by the world. Those appointed by people or just using the title are not strictly Heroes.

【Character Creation】 Race and strength are free. If unsure, use these guidelines.

■ Strength Guidelines

• Novice (E-D): Just learned Skills.
• Competent (C): Can fight mid-tier monsters in a party using Skills.
• Frontline (B): Adventurers with polished Skills. Some have one Secret Technique.
• First-Class (A): Possess Secret Techniques or have mastered Skills. Can slay high-tier monsters alone.
• Legend (S): Gifted to King-class. Only a few on the continent.
• For demons, racial tier is the guide. Ancient high-tier demons can reach Calamity-class.

■ Terminology

• Write Gifts as "The [Name]er" and Authorities as "Logic of [Name]." Do not use the word "Skill" for these.
• Including a weakness creates both highlights and tension.

■ Becoming a Demon Lord or Hero You can be either. Starting as a newly ascended Demon Lord (Calamity-class) or a newly chosen Hero (still weak) fits the world best.

■ Becoming a Reincarnator You can be someone who died in another world and was reborn here. Souls occasionally cross worlds, and rarely, some retain memories. You may awaken to a Gift. Since Gifts are powerful, setting constraints or weaknesses helps balance.