Chapter 9. Primary and Adjacent Worlds: A World Must Be Able to Admit Residents

In the previous chapter, we chose whom to bring. Now we choose the world that person will enter. Chapter 10 draws the faces of the individual characters who live there.

Worldbuilding is not explained. It is shown as a place where one can live.

When designers hear the word worldbuilding, they usually think first of a lore bible. That is only half right.

There is a map of the continent, a count of the races, a war from a thousand years ago, a pantheon of gods, and a unit of currency. We believe the world grows deeper as thick setting documents pile up. Yet to an ordinary person standing before the first screen, these settings are not depth but a wall. If five proper nouns—names of people and places—pour out at once the moment the first screen opens, an ordinary person does not feel the world’s thickness. They first inherit a list to memorize. They did not enter to learn about a thousand-year-old war. They came to see whether this is a place worth living in.

We must stop the habit of measuring worldbuilding by the amount of setting. In a first experience, worldbuilding does not teach people; it admits them. A world must be able to let residents move in. This is another sentence the book repeats. No matter how intricately a world is built, if there is no place for a person to enter and live, it is a museum, not a place of life. The question to ask when designing a world is therefore not “How deep is this world?” but “From where will we move someone into this world?”

Let us define the term in advance. In this book, a world is not a unit of setting but a unit of ways of life. When we speak of a world where people dress and care for characters or a world where they enjoy brief challenges, we do not mean separate lands with different settings. We mean neighborhoods that differ in what people do while living there. Setting and lore are merely the background laid beneath the neighborhood. What this chapter separates into primary and adjacent is always the way of life.

Which World Will Receive the Webtoon Reader?

Return to the fictional character game. We have chosen to bring in one of the candidates drawn in Chapter 8: a reader who binge-read webtoons. To bring this person, we must choose the central world where they will remain most deeply and the nearby worlds attached to it.

What world does a webtoon reader currently inhabit? It is a world where they read one episode at a time, wait for the next, give their heart to favorite characters, and immerse themselves in stories through vertical scrolling. When we bring this person into our game, our central world must not be too far from the place where they lived. If the game’s primary world centers on rapid combat and competition, this person feels alienated from the entrance. Migration does not occur when the old neighborhood and the new one are too far apart.

We therefore set the central world as “a world with stories that flow alongside characters.” This is the primary world: the place that answers in one sentence what this game is, where the greatest number of people will live. Beside it, we place several nearby worlds: one where people dress and care for characters, one where people loosely mingle with others who like the same character, and one where they enjoy brief challenges. These are adjacent worlds, neighboring districts within walking distance that a person who entered because they liked the primary world can naturally step into.

The important thing here is a sense of distance. If an adjacent world is too detached from the primary one, it is another country, not a neighbor. Suddenly pushing a strict ranking-competition world at someone who came for a story makes them feel they entered the wrong place. But if the adjacent world is identical to the primary one, there is no reason to move. An adjacent world must therefore sit at a subtle distance: close enough to the primary world, yet offering at least one new flavor.

Translated into practice, this sense of distance becomes a standard: every world of origin lies at a different immigration distance from ours. A webtoon reader, a short-form scroller, an idol fan, and a player of another game all begin in different neighborhoods. Some origins are near migrations. A webtoon reader who gave their heart to characters and followed stories only has to cross one neighborhood to enter our character-centered story world. Some origins are far migrations. A person trained by rapid combat and efficiency must set down half of what their hands know to enter a leisurely world of care. Some origins are dangerous migrations: the expectations they bring collide directly with our world’s grammar, so poor guidance sends them back from the entrance carrying only aversion. Bringing a fan who cannot bear seeing their favorite graded into a ranking-competition world is such a case. These three are not permanent labels attached to an origin, but variables moved by design. Guide the same fan origin into a caring world and it is a near migration; take them into ranking competition and it becomes dangerous.

To measure distance by more than intuition, split it into two components. The first is the proportion of actions brought from the origin that work unchanged in our world: the reuse rate of hand habits. The other is the number of expectations brought from the origin that our world directly violates: the expectation-collision count. A low reuse rate means a far migration. Even one collision makes it dangerous if it touches a core expectation, such as assigning a grade to someone’s favorite. Once split this way, Appendix B’s immigration map can be drawn by scoring rather than intuition.

The practical standard is simple. The primary world brings people through near migration. It deserves to be primary only if it is the place where the largest number of people can settle across the shortest distance. Adjacent worlds bring people from the next distance, guiding far migrations toward them gradually and declining to seize dangerous migrations forcibly on the first screen.

Many readers will need to reverse the direction. In a live game whose world is already defined, rather than a new project, we do not choose people first and then choose a world. We unfold the world and look for people. Start with origins whose immigration distance to our world is shortest, place entrances and advertising where those origins gather, and inspect the first action that reuses their hand habits. Only the order reverses; the yardstick of distance remains the same.

In MEJE Aidong World, the primary world is one where fans personally dress and care for Aidong resembling their favorite idols. They meet a puppy, frog, or cat, dress it with their own hands, and make it theirs. Beside that world is one where Aidong are matched into groups and their chemistry tuned, and another where fans look at Aidong raised by others. A fan who enjoyed dressing a favorite enters the customization world. A fan who likes socializing is pulled further toward the group-and-chemistry world. Even in the same neighborhood, there are several places to live.

The First Screen Is the Entrance to a Neighborhood, Not City Hall

Here, we narrow the migration metaphor to first-screen design. The first thing a person considering a move sees is the neighborhood entrance. Within seconds they judge whether the street is clean, what expressions people wear, and whether they would fit in. Our game’s first screen is exactly this entrance. If the visitor feels, “I could live here,” within those seconds, they step inside. If they feel, “This is not my neighborhood,” they turn back.

A common mistake is building city hall at the neighborhood entrance. It means handing over registration forms the moment someone enters, making them memorize the world’s rules, issuing identification—in other words, dumping world settings onto the first screen. Make a person register as a resident when they only came to inspect the neighborhood and they turn away before looking around. They must like the neighborhood before wanting to register; the order is reversed.

This metaphor extends only through the first screen. Turning a visitor into someone who lives inside is the job of the first experience. What keeps them there for a long time after they begin living is not this book’s subject. We design the first impression at the neighborhood entrance and the first alley they can enter and explore.

The Proper-Noun Bomb: A Convention Games Love

Since this chapter deals with worlds, let us place one game convention at the checkpoint: the habit of pouring the world’s proper nouns and settings onto the first screen all at once.

Games love the proper nouns of their worlds. Names of races, regions, factions, gods, and events rain down in the first screen or opening cutscene. “In the kingdom of Beltaine on the continent of Arcania, ever since the war against Morgath, Lord of Shadows, a thousand years ago…” Where did this convention come from? From thick fantasy novels and the openings of blockbuster RPGs. To a person already deep inside the world, these proper nouns prove its thickness. The more names there are, the more real the world feels.

Many ordinary people do not share this agreement. Throw five unfamiliar proper nouns at an idol fan or webtoon reader on the first screen and they encounter an entrance exam, not the depth of a world. The moment they feel there is something to memorize, they decide the game is too complicated for them. A gamer reads proper nouns as “mysteries I can learn later,” while an ordinary person reads them as “an entry barrier I cannot pass unless I understand now.” The same screen is a promise to one side and a cost to the other.

The fee this convention charges ordinary people is attention. Remembering an unfamiliar name carries a high cognitive cost, and the first screen is where that budget should be spent most sparingly. A proper-noun bomb spends the whole budget there, leaving no attention for the first action that actually matters. Preserve the essence and change the form. Introduce the world on the first screen through mood rather than names. Let color, sound, and character expressions first convey whether this neighborhood is warm or cold, leisurely or busy, safe or dangerous. Proper nouns can be learned one by one as the person begins living there and walks around. A world is not something to memorize, but somewhere to live.

One more convention belongs at the same checkpoint: the opening cutscene that explains the world. Beginning a dense world with a long video showing it in its entirety is an old convention. Where did those several minutes—laying down a thousand years of history, introducing factions, and foreshadowing destiny—come from? The solemn introductions of blockbuster games. Gamers treat the cutscene as a trailer for the world and sit through it because it is the first scene of the place they will soon inhabit. Ordinary people receive the same cutscene differently. To them, an opening cutscene is not a preview but waiting time that blocks control. They want to touch the game, but the screen ignores them for several minutes, no different from loading. A video that promises a world to gamers feels like time with hands tied to ordinary people. The same screen is a preview to one and a wait to the other. The fee this convention charges ordinary people is time. The moments just before starting are the most expensive time on the first screen, and a long cutscene charges them first. Some acclaimed blockbusters require a long period of following before the player is free to roam. Assassin’s Creed III is often mentioned for such a long introduction. Its weight is attractive to someone immersed in the story, but to a person with only a brief moment to try it, it is simply time with their hands tied.

Preserve the essence and change the form. Well-designed openings go the other way. They tell us only that there was a war, there is a princess, and there is an enemy, then release the remaining fragments when they become necessary. The world’s first impression seeps into the background while the person moves their hands rather than being spoon-fed through video. If something must be shown, make it skippable. Let the person touch first, then let one fragment flow at a time when they stop to rest.

The two inspections can be joined in one rule. Proper nouns and cutscenes are not absolute evils. Their value depends on whether those names exist in the viewer’s prior experience. For the original fan from Chapter 8, an entry opening with scenes and names from the source is the familiarity of Chapter 5 and becomes a welcome. For someone unfamiliar with the original, the same screen becomes material to memorize and an entrance exam. Do not ask whether to include a cutscene. Ask whether the names exist in the prior experience of the person entering through this door.

▶ Three Questions to Apply to My Screen

Does the first screen explain the world, or admit someone to live in it?

How many proper nouns did we throw onto the first screen? Have they become material to memorize?

Did we give the newcomer a role as a resident of this world?

If the first screen begins with resident registration, the visitor turns back before looking around.

So Choose One Primary World and Several Adjacent Ones

Once we view worldbuilding through admission, the first-experience decision becomes clear: choose one primary world for our game and two or three adjacent worlds beside it. The primary world answers “What is this game?” in one sentence. Adjacent worlds are neighbors within walking distance for people who liked that answer.

Place the immigration candidates drawn in Chapter 8 on this map. Through which world entrance will the webtoon reader enter? Where will the idol fan remain longest? Which alley will the short-form viewer explore fastest? Each candidate has a different entrance and a different place to remain. Push everyone through the same entrance and someone inevitably lands outside their neighborhood. Targeting everyone ultimately means designing no entrance clearly.

If we create several entrances, we can later separate them and see which entrance leads people deeper inside. If many people turn back immediately from one world, we have reason to suspect that we built city hall at that neighborhood entrance.

But even after choosing worlds and separating entrances, the world itself does not stand before the door to greet people. Before the street’s atmosphere, what catches the eyes of a first-time visitor is the face of someone who lives there. The next chapter chooses that face. We move to the character who first translates the world and the senses through which that character draws people in.

Reference Content

Cases in other media where this chapter’s concepts are visible.

Video Games

Assassin’s Creed III: It is often mentioned for the long introduction before free movement. That length gives weight to someone immersed in the story, but to someone who only wanted a brief touch, it is time with their hands tied.
The opening of Half-Life 2: After stepping off the train into City 17, the player walks past announcements, posters, and people shoved by soldiers, directly experiencing an oppressive world without explanation. Refer to its first-alley design, where the world seeps into the background while the player moves rather than being spoon-fed by a cutscene.
The opening of Animal Crossing: New Horizons: Upon arrival on the deserted island, Tom Nook has the player pitch a tent and collect branches for a welcome party, showing “this is how you live here” through small tasks rather than world settings. Refer to it as the residential life-sim opening closest to MEJE’s primary world of dressing and caring for a favorite Aidong by hand.

Live-Action Film

The Star Wars opening crawl: Three short paragraphs establish only the state of the Empire and Rebel Alliance. When the words disappear, the camera tilts down and drops immediately into a spaceship chase. Refer to its sense of opening length: lay down only a handful of political context and let the audience touch the action, rather than using a long explanatory cutscene.

General Apps

Duolingo onboarding: The app that divided origins through a placement test in Chapter 8 appears here from another angle. It postpones signup and lets people complete the first lesson immediately, then suggests creating an account when they want to save progress. Refer to the ordering that avoids making the first screen city hall: let someone live there first, then recommend registration, rather than beginning with resident registration at the neighborhood entrance.

The remaining reference content is collected in the “Chapter 9 Appendix” at the end of this chapter (collected as Appendix D in the book edition).

Design Note ▶ Try It Yourself

Write our game’s one primary world in a sentence: “Our game is a world where ____.” Describe not the setting, but what people do while living in that world.

Beside it, write two or three adjacent worlds. Estimate how close each is to the primary world through its hand-habit reuse rate and expectation-collision count, then add one line naming who—which immigration candidate—will enter and live there.

Next, write three pieces of world information to ban from the first screen: one proper noun that demands memorization, one long cutscene that spoon-feeds history or setting, and one piece of lore unnecessary for living there now. Remove them in advance and what should remain becomes clear. Finally, write one thing the first screen would show if it introduced the world by mood alone, without a proper noun. This map grows into Appendix B’s “World Immigration Map.”

If the first screen still makes someone feel “I could live here” after all three are removed, the world admits people. If only things to memorize remain, we have built city hall at the neighborhood entrance; redesign it.

One-line summary: Worldbuilding is measured not by the amount of setting, but by whether there is a place where people can enter and live. One primary world answers “What is this game?” and several adjacent worlds provide neighbors within walking distance. The first screen is a neighborhood entrance; do not begin by registering a visitor as a resident. A world should be felt through mood and lived in, not memorized through proper nouns. Next chapter: We have now chosen the world this person will enter. Next we choose the character who will first translate that world. We move to who lives there, the different senses through which each draws people, and where the people who will love that character came from.

Chapter 9 Appendix: Reference Content Collection

This collection extends the chapter’s argument into examples inside and outside games: worldbuilding should be measured not by the amount of setting, but by whether a person can enter and live there. Choose one primary world and several adjacent worlds, measure different immigration distances for every origin—near, far, and dangerous—and design the first screen as the entrance to a neighborhood rather than city hall. In addition to the section’s central cases, the remaining examples are grouped by medium from video games to offline life. Each item ends with “what to examine,” explaining what designers should observe. The reading method is simple: see whether each world enters through proper nouns and explanation or through mood and action, and what narrows the distance between the person’s former home and the new world.

Video Games

Elden Ring / Dark Souls: FromSoftware’s games do not lay a thousand years of history over subtitles. They let world history flow through the placement of ruined villages, churches, and cities and through one-line item descriptions. In Elden Ring, the true history of the Golden Order appears only after gathering clues in hidden areas such as the Subterranean Shunning-Grounds beneath Leyndell. Examine how design that lets people learn by exploring rather than memorizing secures both depth and accessibility, and where our world’s settings are buried instead of on the first screen.
The Legend of Zelda: Breath of the Wild: The 2017 game sends an awakened Link into a broad landscape without a long setting explanation. The view before him and distant towers and shrines call his next steps. The neighborhood entrance’s impression arrives before proper nouns. Examine how the first screen gives a direction someone wants to visit instead of information, and how landmarks replace instructions.
Halo / Mass Effect: These series have cosmic-scale settings, yet do not pour the proper nouns of races and factions onto the first screen. They let people learn the world one piece at a time from dialogue and records while moving through missions. Examine how the larger the total volume of setting, the more sparingly the entrance must reveal it, and count the proper nouns appearing in the first hour.
The opening of Portal: Valve’s 2007 puzzle game lets an awakened test subject solve the first room directly while listening only to announcements from the AI GLaDOS. The player learns world and controls simultaneously through touch rather than memorizing rules. Examine this residential opening, which lets people live immediately instead of explaining on the first screen, and the translation performed by an in-world device—announcements—in place of tutorial copy.
The opening of Hollow Knight: The 2017 game places the player, after brief control guidance, in Dirtmouth, a village with only empty houses and streetlamps, then invites them to descend through a well despite an elder’s warning. It does not explain who or why. The lonely impression at an empty neighborhood entrance conveys the weight of a fallen kingdom first. Examine when someone first feels “I want to know about this world” in an opening where mood precedes setting, and the order in which lore is released only after that curiosity arises.
The opening of Disco Elysium: The 2019 game awakens an amnesiac detective in a ruined hotel room. Rather than listening to a world explanation, he gropes first through his own condition, learning the world at the player’s pace. Examine how setting clues are released one piece at a time as needed rather than all at once, and how the protagonist’s ignorance excuses the player’s ignorance.
Kingdom Hearts / Xenosaga: Terms unique to the series—Heartless, Nobody, Keyblade, and others—accumulate over installments and are often cited as an entry barrier for newcomers. A name that is a mystery to deep fans becomes an entrance exam for a first-time visitor. Examine this reverse example of how a proper-noun bomb becomes a cost, and count how many names unnecessary for the moment appear first at our entrance.
Minecraft: The game begins by placing someone in a field without explanation or a stated objective. They learn the world’s rules by hand while gathering wood and surviving the first night. Beside the survival world is a creative world for building freely, attached through the same block grammar, so a person familiar with one can walk into the other. Examine the structure in which primary and adjacent worlds share hand habits and shorten immigration distance, directly realizing the definition of a world as a way of life rather than a unit of setting.
Fortnite: Beside its primary battle-royale world, it has attached Creative modes for making and playing, events centered on performance and socializing, and adjacent worlds such as LEGO Fortnite (2023). The same avatar and locker follow people into every world. Examine the distance arrangement where adjacent worlds remain close enough to the primary yet offer one new flavor, and how the shared household of an avatar reduces the burden of moving.

Mobile, Apps, and Services

A first impression filled with examples instead of an empty screen: Collaboration tools and note apps fill first entry with sample documents and projects rather than emptiness, conveying through atmosphere “this is what people do here” instead of making someone memorize settings. Examine whether examples furnished like a model home before move-in guide the first action, and whether they are easy to remove once no longer needed.
Instagram Reels: This vertical short-video section added in 2020 is often described as designed so that the hand habit of people who lived on TikTok—vertical swiping—works unchanged. It becomes a neighboring district within the same app for existing Instagram residents and a near migration for people from TikTok. Examine how importing another neighborhood’s hand habit shortens immigration distance, along with the cost to existing residents who feel that their neighborhood changed.

Film and Animation

The opening of Spirited Away: The 2001 film follows Chihiro through a tunnel and an empty restaurant street without explanatory dialogue, until night falls and gods appear. The audience receives the other world through mood at the same pace as Chihiro. Examine an opening that makes the world felt first through scenery and light without proper nouns, and the structure in which the protagonist’s confusion carries the audience’s confusion.
Episode 1 of Attack on Titan: It first shows peaceful daily life inside the walls, then drops the audience directly into the incident of a Colossal Titan breaking through. The world is experienced through an event, not taught as a setting lecture. Examine, in this in-medias-res opening without a preliminary background explanation, how a few minutes of daily life support the weight of the shock that follows.
Episode 1 of Made in Abyss: It begins with daily life in Orth, the town at the edge of the enormous pit, and immediately lets the audience experience cave-raiding culture through action, living the world’s mood and rules without explanation. Examine how the first episode gives the impression of the neighborhood entrance before a setting lecture, and how the world’s central rules arrive naturally inside a character’s daily work.
Mad Max: Fury Road: The 2015 film drops the audience directly into a chase after a few short lines of monologue. Art direction and character behavior, not explanatory dialogue, reveal the rules of a wasteland ruled by those who control water and oil. No knowledge of the previous three films is required. Examine what prevents the audience from getting lost even when explanation is reduced to an extreme, and how clear desires and a single-direction route replace a setting lecture.

Literature and Narrative Technique

Tolkien’s The Silmarillion and The Hobbit: Even within the same world, The Silmarillion, which begins with genealogy and myth, and The Hobbit, which admits readers through one hobbit’s adventure, have different immigration distances. Depth is not the same as accessibility. Examine an arrangement that provides several entrances to the same world but makes the first a near migration, and ask whether we are putting our world’s Silmarillion on the first screen.
In medias res: A narrative method used since epic poetry that drops readers into an event rather than laying down the background first, making them live in the world. Examine what holds readers when explanation is postponed, and how long tension in the event lets them tolerate the blanks in the setting.

Music

Janelle Monáe’s Metropolis series: It builds the dystopian city of the android Cindi Mayweather one fragment at a time through songs and inter-song skits rather than a setting bible. Examine residential worldbuilding that lets the world seep into the background while someone enjoys the work, and the order that makes the song good before requiring the setting.

Board Games and TRPGs

Gloomhaven’s first scenario: Although it is a large campaign board game released in 2017, it does not make players read the entire setting book. It lets them live in the world through one small first adventure. Examine the method of reducing rules and world to one session’s portion, and the restraint of carving a smaller first entrance for a larger world.
A TRPG session zero: Before the main game, participants meet to align tone and mood, what they want, and what they wish to avoid. Before making anyone memorize the rulebook, they first see whether this is a place where people can live. Examine how agreeing on the neighborhood’s mood before moving in reduces abandonment, and whether our onboarding has a stage corresponding to session zero.

Offline and Everyday Life

Disneyland’s “weenie,” the attention-drawing landmark: A term associated with Walt Disney, it refers to a distant landmark such as a castle that catches the eye and draws people inward. The scenery points the route without instructions. Examine design where landscape rather than names and maps creates movement, and what serves as the weenie on our first screen.
Mood design in a museum’s first gallery: Instead of pouring out wall text, museums use the first room’s light and sound to convey what kind of place it is, reducing viewing fatigue. Examine the first-room arrangement that gives atmosphere before information, and whether our first screen is a room of wall text or a room of light.
An IKEA showroom: Furniture is shown not through specification sheets and shelf display, but by furnishing entire living rooms and bedrooms. A person entering can bodily estimate, “This is what living here would be like.” Examine how displaying a way of life rather than specifications draws the imagination of moving in, and whether our first screen shows specs or a household.
Inspecting a new neighborhood before deciding to move: People do not register as residents first. They look at the streets and people’s expressions to judge whether it is worth living there. Examine how the first screen is the object of that inspection and what appears within the first few seconds at our neighborhood entrance.