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Infinite Worlds

Building Worlds

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Creating an entire science fantasy world from scratch can be a daunting task, but this chapter provides easy steps to help you quickly generate nigh-infinite worlds. Whether you’re a player whipping up a home planet for your new character or a GM crafting worlds for other players to explore, simply follow the steps below—tweaking the results as desired—to craft your own worlds!
In the first three steps of creating a planet, you’ll determine your world’s basic physical characteristics, which can inform its inhabitants and provide potential adventure hooks. In Step 4, you’ll determine your world’s various cultural attributes, which flesh out a world’s character and can provide myriad possibilities for adventure. In the final step, you’ll add some finishing touches, perhaps including a few settlements and NPCs using their respective toolboxes on pages 148–151.
By randomly determining your world’s physical and cultural attributes as well as blending their resultant inhabitants and adventure hooks, you can create virtually limitless arrays of science fantasy worlds to explore. Keep in mind that any seemingly conflicting attributes you generate with this process are rich opportunities for storytelling: does your asteroid have a thick atmosphere, a predominantly aquatic biome, and a high level of magic? Perhaps it’s a tiny ocean world with an icy shell, hurtling through space and carrying a magical society of miniature sapient creatures with it.

Step 1: World Type

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You can choose to create a relatively standard terrestrial world—one that’s naturally habitable and replete with one or more biomes (see Step 3)—or you can roll on (or choose from) the Astronomical Object table for the possibility of something stranger. See pages 394–395 of the Starfinder Core Rulebook for more about gas giants, irregular worlds, and satellites.

Astronomical Object

D%Type of World
51–70Gas giant
96–97Colony ship
98–100Space station

Step 2: Gravity And Atmosphere

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Roll once on the Gravity and Atmosphere table to determine your world’s gravity, and then roll again to determine its atmosphere. See pages 395–396 of the Core Rulebook for more about atmospheres and pages 401–402 of the Core Rulebook for more about gravity.

Gravity and Atmosphere

51–60Zero GravityNone
91–100ExtremeCorrosive or toxic

Step 3: Biomes

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Terrestrial worlds are usually predominantly composed of one or more biomes, while other types of astronomical objects might have artificial or magical regions of a particular biome. You can select or roll a single biome on the Biomes table (a solely aquatic world could represent an ocean planet, for instance), or you can roll several times to produce a world with multiple prominent biomes, ignoring any results you don’t want to include. You can treat any duplicate results as an indication that the duplicated biome is more common than the others. For example, if you rolled aquatic twice and forest once, you might have a forested world that’s 60% water or a world of underwater forests with canopies that extend above the waves.



Biome Subsections

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Whichever biomes your world has, pages 48–95 provide detailed information about each, including tables for inhabitants, adventure hooks, and player options that, while related to the biome, can be used anywhere in the galaxy.
Biome Overview: Each biome provides a wealth of flavorful information that can help GMs and other players immerse themselves in fantastical adventures. Also included is information about adventurers that might hail from such places, what worlds of that biome might look like, and other general details. Finally, a rules and reference section highlights existing rules that will come in handy for that biome.
Biome Inhabitants: A world’s inhabitants are presented in this book as either sapient or threat creatures. A sapient creature can generally think and reason, and they’re likely to form civilizations, interact meaningfully with PCs, need help, or even serve as archvillains. Threat creatures are generally (but not always) non-sapient creatures that serve as a threat to the world’s inhabitants or the PCs.
Using the inhabitant table provided with each biome, you can roll a world’s inhabitants as you would a biome: once for a world that contains only a single such species or multiple times for a more nuanced world, again using repeat results as indicators of, for example, relative population size or political power. Roll separately for sapient creatures and threats.
Note that inhabitant creatures are followed by superscripts that indicate the books in which you can discover more information about them. In such superscripts, “AP” followed by a number refers to a volume of the Starfinder Adventure Path; for example, “AP10” refers to Starfinder Adventure Path #10.
Biome Adventure Hooks: Each biome has a table of related adventure hooks. These open-ended story prompts can be combined with other adventure hooks, especially those in the Cultural Attributes section (below) to create unique adventures based on your world’s particular composition and culture.
Player Options: Each biome presents thematic player options available to any character who meets the prerequisites. Furthermore, these options aren’t restricted to such biomes, although PCs might want to incorporate such connections into their backstories!

Step 4: Cultural Attributes

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Besides its basic physical features, a world is heavily influenced by the presence—or absence—of various cultural influences. Each of the following attributes has a corresponding section in this book (starting on the page given in parentheses) that provides in-depth details about its impact on a world as well as inspiration, adventure hooks, GM tools, and player options related to various levels of that attribute.
Accord (page 96): Roll 1d6 to determine whether this world is a low accord (1–2), medium accord (3–4), or high accord (5–6).
Alignment (page 102): First, roll 1d6 to determine whether the world is predominantly chaotic (1–2), neutral (3–4), or lawful (5–6). Then roll 1d6 to determine whether the world is predominantly evil (1–2), neutral (3–4), or good (5–6). For example, rolling 2 and then 6 would result in a chaotic good world (detailed further on page 104). Two results of 3 or 4 mean the world is predominantly neutral (page 105).
Magic (page 108): Roll 1d6 to determine whether this world is low magic (1–2), medium magic (3–4), or high magic (5–6).
Religion (page 116): Roll 1d6 to determine whether this world is low religion (1–2), medium religion (3–4), or high religion (5–6).
Technology (page 122): Roll 1d6 to determine whether this world is low technology (1–2), medium technology (3–4), or high technology (5–6).

Step 5: Finishing Touches

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Each biome and cultural attribute is richly supported in this book’s other sections, but there are more ways you can add enriching details to your new world.
Adventure Hooks: With just a couple biomes and the cultural attributes set for your world, you have more than 100 adventure hooks to randomly roll or choose from! Better yet, you can generate nigh-infinite ideas by randomly rolling adventure hooks from different tables and combining them in interesting ways. These ideas aren’t just for GMs looking to challenge PCs, either. Other players might use such hooks to flesh out their background and explain how they got into adventuring—or what they left their home world to escape.
NPCs: While you likely don’t want to detail every sapient individual on a world, it can be helpful to have a few compelling NPCs to serve as points of contact, villains, companions, and the like. You can use the NPC Toolbox on pages 148–149 to easily generate an alien name and species, along with some memorable quirks. You can also roll on the Influential Associate and Party Relationships tables (pages 11–13) from the Backgrounds section of this book for ideas on how an NPC might relate to some or all of the PCs.
Settlements: As with NPCs, you likely want to detail a few major settlements in each world to serve as a landing site or home base. The Settlement Toolbox on pages 150–151 can help you generate rich locations with quirks and challenges to shape a settlement’s character. There’s also a table featuring a bevvy of potential locations for a science fantasy setting—roll a few times to see which locations are of particular prominence in a settlement, and you’ll know a lot more about the people who live there.
Other Features: Feel free to add any features not covered by this system to your world, its places, or its people. Other Starfinder books, such as Starfinder Pact Worlds and Starfinder Near Space, provide treasure troves of interesting science fantasy worlds and locations to inspire your creations!

The Deck Of Many Worlds

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As an alternative to using the tables presented in steps 1–4, you can use cards drawn randomly from the 100-card Starfinder Deck of Many Worlds accessory to quickly generate a world’s type, gravity, atmosphere, biomes, cultural attributes, inhabitants, and adventure hooks—all in a few seconds by simply combining a few cards. The cards themselves provide millions of possible combinations, and that’s before you pair them with the information and tools presented in this book!