Worldbuilding Tip: The Sizing System — How Size Classes and Grades Shape Everything from iPhones to Architecture
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Last time, I argued that species don't make cultures — that the Imago Dei framework, applied consistently, produces a world where Leonites are Nigerian and Russian and Syrian and Korean, where there are no Leonite countries, and where culture and history and faith bind communities far more powerfully than shared biology. Mixed-species society is not an idealistic aspiration in this world. It is the natural state, and the biology itself predicts why it works.
But that argument raises an immediate practical question.
If a Vulpen and a Leonite are both members of the same church, the same neighborhood, the same family in some cases — sitting in the same pews, walking the same streets, attending the same schools — how does a world built for human-scale bodies actually function when the bodies in question range from the size of a house cat to the size of a polar bear?
The answer is the Sizing System. And it is one of the most practically generative decisions in this entire method — because once you work it out, it touches everything.
The Basic Structure: Three Classes, Three Grades
The Sizing System divides all anthropomorphic species into three Size Classes: Small, Large, and Giant. Within each class, there are three Grades — Grade I, Grade II, and Grade III — representing finer gradations of size from smallest to largest within the class.
The result is nine distinct size tiers, spanning the full range from the smallest Small Grade I species to the largest Giant Grade III — a range that, in practice, represents a difference of several hundred pounds and several feet of height between the extremes.
Size Class and Grade are not determined by height alone. The classification system uses height, weight, and body mass together — because a species can be tall without being heavy, or compact and dense in ways that don't show in height. Both dimensions matter, and both are factored into where an individual falls.
This has real consequences for where individuals land in the system, and it prevents the kind of simple "tallest person wins" logic that might seem intuitive at first.
The Roster, Class by Class
Small Class covers the smaller carnivorous species in the roster. Small Grade I includes the Fennic Fox and the Wild Cat — the smallest members of the world's anthropomorphic population. Small Grade II includes Otters on the larger end and species like the Fossa and Ocelot on their smaller end. Small Grade III is where the larger Small species land: Giant Otters, larger Vulpens, larger Fossa and Ocelots. Marcelo — an adult Vulpen — is a Small Grade III, which places him at the top end of the Small Class.
Large Class is the most populated tier, covering the mid-range carnivores that form the majority of the anthropomorphic world's population. Large Grade I includes Calatrans (coyote-people), Lynxes, Pumas, and Lupenites on the shorter end of their natural range — Sophia, Sergei's future wife, stands 5'2" as an adult with a substantial, heavy-boned frame, and she is classified as Large Grade I because the threshold for Grade II requires both the height and weight markers to be met, not just one. Large Grade II is where most Lupenites fall — Boris and Larissa and their children are solid Grade IIs — along with Pardinians like Igor and the Jabutuns. Large Grade III holds the Hyeanids and Ocanians; Marek is a Large Grade III Hyeanid, and the difference between him and a Grade II Lupenite is visible.
Giant Class is where the Ursinians and the big cats land. Giant Grade I is the Black Ursinians — Rowland is a good example — large and heavy but on the smaller end of the Giant range. Giant Grade II is where Leonites and Tiscythians sit: Marshal is a Giant Grade II Leonite. Giant Grade III is the Grizzly and Polar Ursinians — the largest members of the anthropomorphic world by height, weight, and mass combined.
Why Height Alone Doesn't Determine Grade
This is worth dwelling on, because the multi-factor nature of the system produces results that might seem counterintuitive until you understand the logic.
Vladimir Volorsky — one of Boris and Larissa's eldest twin sons — stands 7 feet tall without his ears counted. That is exceptionally tall for a Lupenite. It is also only six inches shorter than Marek, who is a Large Grade III Hyeanid. If height were the only variable, you might expect Vladimir to approach Grade III classification.
He doesn't. Vladimir is solidly Large Grade II.
The reason is that height is only one dimension. Marek is not just taller than most Grade IIs — he is far heavier, with a broader, denser bone structure and significantly greater muscle mass. The total body profile — height, weight, and mass together — places him in a categorically different tier than Vladimir, despite the relatively small gap in raw height. Vladimir is a very tall Grade II. Marek is a Grade III. The classification reflects the whole person, not a single measurement.
The same logic applies at the other end of the range. Sophia has a large, heavy bone structure for a Lupenite her height — more substantial than many Calatrans or Pumas who share the Grade I classification. But she does not meet the threshold for Grade II in either height or weight, and the system requires both. She is Large Grade I. The bone structure is noted; it does not override the classification.
The practical threshold for Large Grade II, as a reference point, is approximately 5'8" and 200 pounds — roughly what you might think of as an average, unremarkable adult human person. Anyone who meets both criteria is in Grade II territory; anyone who falls short of either remains in Grade I, regardless of how they compare on the single dimension they do meet.
What the System Has to Account For: The Built World
Here is where the Sizing System stops being an abstract taxonomy and starts being a worldbuilding engine.
A Small Grade I Fennic Fox and a Giant Grade III Polar Ursinian are both members of the same world. They attend the same schools, work in the same offices, worship in the same churches, pass each other on the same sidewalks. The physical infrastructure of the world has to accommodate both — and the nine-tier spread means that "accommodate" is doing serious work.
Public buildings solve this problem universally. Schools, hospitals, government buildings, offices, transit systems — anything designed for shared use is built to the full range. Doorways, seating, hallways, staircases, restrooms — all of it is scaled to function for every Size Class and Grade. A Giant Grade III Ursinian walking into a courthouse and a Small Grade I Wild Cat walking into the same courthouse will both find a space that was designed with them in mind.
Personal possessions work differently. The things that belong to a specific individual — housing, clothing, vehicles, furniture, personal technology — are manufactured and sized for that individual's class and grade. There are not nine different sizes of "one universal product." There are nine different products, each designed for its tier.
Marshal and Marcelo both carry iPhones. They are not the same iPhone. Marshal's phone is a Giant Grade II model — sized for his hands, his grip, his visual range. Marcelo's is a Small Grade III model. They are running the same software, connecting to the same networks, doing the same things — but the physical object is different because the physical person is different. The same is true for cars, apartments, clothing, furniture, and every other personal possession that depends on a body's dimensions to function correctly.
Apartment buildings and housing developments are built with specific size classes in mind during the planning process. A building designed for Large Grade II residents will have units, hallways, and fixtures scaled to that tier. A Mixed-class building will have units of different sizes, with common areas scaled to the largest expected resident. Developers plan for this the way they plan for any other specification — it is ordinary engineering, not exceptional accommodation.
What the Size Gap Feels Like Socially
Two full Size Classes separate a Small Grade III Vulpen like Marcelo from a Giant Grade II Leonite like Marshal. That gap is not abstract — it is present in every shared physical space, every handshake, every conversation across a table.
And yet it is not, in this world, a source of tension. It is simply a feature of the environment that everyone navigates as a matter of ordinary life. The Leonite priest who serves a mixed parish has learned how to move through a space designed for a range of bodies. The Vulpen student in a classroom with Lupenite and Ursinian classmates has grown up understanding that the physical world accommodates her but was not built only for her.
What the size difference does affect is the texture of social interaction — not its quality. A Giant Grade II Leonite and a Small Grade III Vulpen do not interact the way two Large Grade II Lupenites do. The physical choreography is different: proximity, eye contact, the way a handshake or a hand on the shoulder reads across that gap. A Leonite being careful not to crowd a Vulpen colleague is not performing deference — it is ordinary physical awareness, the same awareness any large person develops in a world that also contains small people.
In a world that has always been mixed, this awareness is not extraordinary. It is just how people move.
How to Apply This in Your Own World
If you are building an anthropomorphic world with a wide size range, the Sizing System offers a template — but the specific structure matters less than the underlying questions it forces you to answer.
First: define your range. How big is the biggest species in your roster? How small is the smallest? The greater the gap, the more the built world has to account for it. If your range is relatively narrow, a simpler system may serve. If your world includes species that vary by several hundred pounds and multiple feet of height, you need a principled way of categorizing that variation.
Second: use multiple factors. Height alone produces a system that misclassifies dense, heavy, compact species as smaller than they functionally are. Weight alone misclassifies very tall, lean species. The combination of height, weight, and body mass gives you a more accurate — and more interesting — picture of where individuals actually fall.
Third: let the built world follow the logic. Once you know your size range, ask what it means for the physical infrastructure of your world. Public spaces that are truly mixed-use have to be designed for the full range. Personal possessions have to be sized for the individual. These are not annoying complications — they are the details that make a world feel genuinely inhabited by the bodies that live in it.
Fourth: think about what size does and doesn't determine. In this world, a Giant Grade III Polar Ursinian and a Small Grade I Fennic Fox are equally made in the image of God, equally capable of virtue and failure, equally bound by the moral architecture of the world. Size determines the physical experience of the world. It does not determine moral weight, social standing, or narrative importance. The moment size starts to function as a proxy for those things — the moment the largest characters are automatically the most powerful or important — you have imported a logic the system was designed to prevent.
Size is a physical fact. Like species, it creates pressure. Like species, it does not determine who anyone is.
— Eric Flegal
Want to go deeper? These tips are drawn from the full Anthropomorphic Worldbuilding Guide — a complete PDF resource covering everything from species design to moral structure to narrative architecture. Get the full guide here →
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