[Synopsis] The year is 6020 of the Holy Guide Calendar. A single Earth Dragon has settled in the Stahl Pass, crossing the Central Great Mountains of the Kingdom of Granat. A dragon that eats the steel carried by caravans and hardens its scales with it. People call it the "Steel-Eater." The Steel-Eater crushed the mining town of Erz and made its nest at the summit. In a country where it is said "Humanity would have perished long ago without Granat steel," the road of steel has come to a halt.

The Adventurers' Guild has issued a subjugation request restricted to A-rankers. In the post town of Thalheim at the foot of the pass, five strangers from across the continent gather. A former Holy Knight lancer dreaming of dragon hunting. The "Hero of the Port" from Solvain. A dwarven heavy warrior whose hometown was crushed. A snow leopard beastman mercenary from the Empire. An elven spirit-user, the only one who has ever seen a dragon.

This ragtag group of five challenges a Calamity-class dragon.

[You Are] You can be a companion climbing the pass with the party, a resident of the town at the foot, or a demon living in the mountains. Race, appearance, strength, and purpose are free. None of the party members know your true identity from the start.

• If joining the party: As the sixth dragon hunter. Even if you aren't A-rank, you'll be relied upon if you're a guide familiar with the pass.
• If a resident: A merchant from a stalled caravan, an innkeeper, a Guild clerk, etc.
• If a demon: A high-tier demon (Calamity-class) who has lived long will be a good match for the five.
• You can also be anything else, such as another adventurer targeting the Steel-Eater.

[How to Start] The story begins at the adventurers' inn in Thalheim. The night before departure, when the five strangers first meet.

[The Party] Estelle, fired up for the dragon hunt, takes charge; the boisterous Hagen laughs; the silent Ilsa keeps watch; and the quiet Linden looks after them with a sigh. The "Hero of the Port" Ragna joined alone, leaving his companions behind. He is the leader of the Gray Swallows from "The Noisy Hero Party's Dungeon Crawl."

[The Steel-Eater and the Pass]

• The Steel-Eater is a Calamity-class Earth Dragon. It has no wings and cannot fly. Its scales are hardened by the steel it eats, and ordinary blades won't pierce them.
• The pass takes three days from Thalheim at the foot to the nest at the summit. Halfway up are the ruins of the crushed mining town, Erz.
• The area above Erz is the Steel-Eater's territory.

■ Races

• Humans: The most numerous. Six thousand years ago, they first gained magic through the blood of the Saint.

• Elves: Long-lived and excel in magic. They live in the frontier forests and the northern Empire.

• Dwarves: Possess a craftsman's spirit; the heart of magic tool manufacturing. They live in the mountains of Granat.

• Beastmen: Possess high physical capabilities. They form the core of the Imperial military.

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

■ History

• 15,000+ years ago: Ancient Civilization Era. Humanity, lacking magic, flourished through technology.

• 10,000 years ago: The Ancient Civilization perished. No one passed down what happened; only ruins remain in various places.

• 10,000 to 6,000 years ago: The Four Thousand Year Void. Humanity, lacking magic, existed only to be eaten by demons.

• 6,000 years ago: Saint Alicia shared her blood with humanity, and people gained magic for the first time. The Holy Guide Church, which enshrines the Saint, was founded.

• Approx. 400 years ago: King Solvain established the Adventurers' Guild.

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

• Eisenland Empire: A northern military power where magic research flourishes. There is no Adventurers' Guild; the military handles monsters. They are in a continuous war with the Demon King Granvel in the northeast.

• Kingdom of Calendia: A granary of vast plains stretching from the west to the center. Home to the Great Labyrinth Altum and the Labyrinth City Rimen.

• Kingdom of Granat: A land of dwarves and craftsmen in the Central Great Mountains. The heart of weaponry and magic tools.

• Kingdom of Solvain: A land of sea and trade in the southeast. Headquarters of the Adventurers' Guild.

• Kingdom of Lumiel: A peninsular nation in the south. Home to the Holy City Sangria, the seat of the Holy Guide Church.

• Frontiers: The Great Sylvarie Forest of the elves, the White Frozen Plains where Progenitor Dragons are said to live, and the Southern Volcanic Belt.

To reach Authority, one needs three things: a singular soul, accumulated training, and the emotions directed by others. Talent alone or effort alone is not enough. Heroes are the only exception, chosen by soul alone. Against an opponent of a vastly different tier, attacks themselves will not even land.

[Magic] ■ Attributes Six attributes—Fire, Water, Wind, Earth, Light, and Dark—plus the non-attributed Null. Aptitude is innate; most have one, and two is rare. Ice derives from Water, Lightning from Wind, and Plants and Metal from Earth. Null (Physical Reinforcement, Space, Mind) can be used by anyone.

■ Mana Capacity Determined by innate talent; lineage does not matter. A commoner may suddenly produce a genius.

■ Ranks Producing fire is a Skill; a spell that burns a mountain is a Secret Technique; dominating flame itself is an Authority.

■ Incantation Not mandatory. The more experienced the user, the less they chant.

■ Space Magic Sub-space storage has been turned into magic tools, used commonly 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 excels at this. However, the dead do not return.

■ Dark Attribute Not a sin. However, the prejudice that "Darkness is ominous" remains strong, and many users hide it.

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

■ Summoning Familiar, Summoned Beast, and Spirit Summoning are all legal. Only Demon Summoning is the gravest heresy.

■ Magic Tools Granat and the dwarves are the masters. Magic stones, Transfer Stones (for escaping to base), Bags of Holding, Floating Lanterns, scrolls with sealed magic, etc.

[Martial Arts] Swords, spears, axes, blunts, whips, bows, and unarmed combat also span Skill, Secret Technique, and Authority, just like magic. The dividing line is 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 one to swat away flying arrows. Perfecting this reaches A-rank.

■ Secret Technique Power extends beyond the weapon. Slashing waves or impacts that reach beyond range, Blink, strikes that shatter castle walls, or techniques that imbue weapons with attributes.

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

■ Demon Kings Any demon who reaches King-tier is called a Demon King. No one knows how many there are. The known one is the Conquest King Granvel, who continues to fight the Empire. Demon Kings grow through reverence and fear. A newly ascended Demon King is about Calamity-class; they grow stronger as they are feared, and when fully grown, they rival a nation's military power.

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

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

■ Growth Since they are chosen without training or the emotions of others, a newly chosen Hero is weak. They grow through the hope directed at them by people, and when fully grown, they rival a nation's military power.

■ Real vs. Self-Proclaimed There is no visible mark. A real Hero possesses an Authority bestowed by the world. Those appointed by humans or who simply call themselves such are not strictly Heroes.

[Character Creation] Race and strength are free. If unsure, following these guidelines will help you fit into the world.

■ Strength Guidelines (See the image above for ranks and tiers)

• Fledgling (E–D): Just learned Skills.
• Competent (C): Can fight mid-tier monsters in a party using Skills.
• Front-line (B): Adventurers with polished Skills. Some possess a single Secret Technique.
• First-class (A): Those with Secret Techniques or perfected Skills. Can defeat high-tier monsters alone.
• Legend (S): From Singularities to King-tier. Only a few on the continent.
• For demons, racial tier is the guide for strength. Long-lived high-tier demons reach Calamity-class.

■ Terminology

• Write Singularities as <<The [Noun]er>> and Authorities as <<Principle of [Noun]>>. Do not use the word "Skill" for these.
• Writing weaknesses creates both highlights and moments of peril.

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

■ Becoming a Reincarnator You can be a reincarnator who died in another world and was reborn in this one. Souls occasionally cross worlds to be reborn, and rarely, someone is born with memories of their previous life. You may awaken to a Singularity <<The [Noun]er>>. Since Singularities are powerful, deciding on constraints or weaknesses will help you fit into the world.

■ Things Best Avoided Progenitor Dragons and Primordials are special existences that can be counted on one hand. Claiming to be a new one often conflicts with the world setting. If you want to be a strong demon, a long-lived high-tier demon or a newly ascended Demon King is recommended.