Pre-introduction: I’d put off publishing the Seacat rules and mechanics on my blog for ages for two reasons. First, for the last 12 months I’ve been convinced that I’m just about to finish the whole book and that will be the best time to publish the whole thing and the parts on the blog. Second, writing a rulebook, writing content, illustrating it, and laying it out, has been such an all-consuming task that I felt bad about taking time off from that “big task” to do the little things. Like share mechanics and content and art and generally promote what I’m doing and keep the blog lively and fun.
Well, today’s Sunday, so let’s say this isn’t work. This is just me posting some unedited excerpts from Uranium Butterflies, the hero book for the Vastlands.
Magic
“And that is how the leopard got its wings.”
—Anaxrima Voželava, Just So Wizardry, 3rd Edition.
Magic is everywhere in the Given World. It is enchanted. Awash in energies. Alive with Ka. Vibrating with Lei. Gushing with Vir. Threaded with radiations and information spheres and tiny wave-particle machines. Woven into the very structure of the universal simulation of reality.
Or, at the very least, the world is deep and old. Layers upon layers of misinformation and disinformation, reality alteration, and mad distortion coat the globe like the filth of aeons. Wheels and processes churn madly just beneath the skin of the ordinary and everyday. Where does the line between technology and magic and religion lie? The line is a lie.
It is a truth: great powers are waiting to be plucked free by a careless fool styling themselves wizard. But what are they? How do they work? Humans seek patterns. Invent explanations. Time passes. The theories are forgotten, but the practices remain.
Those half-forgotten powers promise so much. Overcome life and death. Ascend to the heavens like the prophets of old. Reawaken the glittering sky cities. Journey beyond the veil of the night into the lands of Everlight and Neverfade.
So many promises. So many fools. So much pain, corruption, mutation, change, and death in their wakes.
How Spells Work
Spells are practical recipes, rituals for ripping mundane reality open and changing it to serve the hero. At best, they are naive and flawed. At worst, they are dangerous, garbled mistakes, misused and misunderstood. Practically, they are treated as a kind of equipment.
Casting Spells
Magic rips reality, imposing otherworldly wrongness on the mundane, so spells hurt. Heroes pay the spell price to begin casting a spell.
Spell Price (in life or stat points) = Magic Cost × Spell Power
Different heroes may incur different magic costs. For example, an explorer with a magic cost of 2 summons a 3rd power Thornstone Obelisk. They pay 6 life or any mix of life and stat points. A witch, with a magic cost of 1, casting the same spell pays only 3 life.
The spell caster’s player narrates the details of the procedure. The hero might cast a spell by reading aloud from a book or dancing to summon a demon. On the other hand, they might just light some dribbly candles in a special order.
Spell Power
Some spells are more potent than others or can be prepared in more effective (and expensive) ways. Higher power spells have a higher spell price and are more dangerous to cast. A hero can cast any spell of any power, but it is dangerous to cast a higher power spell than the hero’s level.
Anyone Can Cast Spells
Any hero can try to cast any spell, whether they have a relevant skill or not, so long as they pay the spell price. If they lack a relevant skill, spell casting is more challenging. The spell price is doubled, and all spell die rolls are made with disadvantage [-], including corruption rolls.
Spell Albums
Shortly before choking to death on a chicken bone at the Pelegrine Festival of Beaux Magics, the abmortal and much revered grand magus Anaxrima Voželava published the famous 6th Final Edition of Just So Wizardry: Magic for Beginners. There, she arranged the 79 approved magics and 21 incidental spells into twenty canonical albums corresponding to the 20 official vedas.
Ever since, some have arranged their own spells into albums. Just as many have ignored the whole idea and gone their own merry way. Still, for the laity, spell albums lend magic an illusory sense of order and reason. In Seacat spells are organized in albums for convenience, not because heroes are restricted to that album of spells by their skills.
Core Spells
Each magic skill (veda) has at least one associated core spell that a hero gains automatically if they have a rank in that skill. Some spell albums contain multiple core spells. In that case, a hero chooses one for their free starter.
Dangerous Magic
Sometimes, often even, magic is dangerous. An unwary practitioner may be corrupted, changed by forces beyond ordinary understanding until they become something not-quite-human. Or not-at-all human if they persist.
Magic is safe if a character has a relevant skill and a level equal to or higher than the spell power. They pay the cost and cast the spell and that’s it.
Magic is dangerous if at least one criterion is true:
1. Character has no relevant skill.
2. Character’s level is lower than the spell power.
3. The spell is marked as dangerous.
Casting a dangerous spell requires a corruption test vs the spell price. Two situations commonly apply (and can cancel each other out):
• Character has no relevant skill: [-] to corruption test. Note that spell price is doubled without a relevant skill (see: Anyone Can Cast Spells).
• Character’s level is higher than the spell power: [+] to corruption test.
When a character fails a corruption test the magic they tried to control twists their body, abrades their soul, and/or changes their personality. Or, at the very least, it burdens them with dark mysteries they were not meant to know.
In game terms, this manifests as various mutations and burdens the character may acquire due to magical corruption (pXX).
Acquiring New Spells
Heroes gain new spells by exploring strange artefacts, as treasure, or as payment for their work. Some simple spells might also be available for purchase from the right purveyor of intergalactic planetary other-dimensional … erm … their eccentric wizard corner store. Casting a new spell without studying it first is always dangerous.
Learning how to use a new spell somewhat safely requires a week’s study. After that time, when the hero casts the spell for the first time, they make a moderate thought test.
If they fail, they misunderstood how the spell works, and it is now dangerous for them. The hero then immediately makes a second test to see if the spell’s first trial casting has corrupted them. If the spell was already tagged as dangerous before the hero tried to learn it, they would suffer disadvantage [-] on their corruption test.
Spells Go in the Inventory
Each spell a hero can cast goes in their inventory. This is the spell burden and is usually equal to 1 stone.
Most spells are not just recipes and bundles of words a hero carries in their head. They are a burden that weighs them down. This might be ritual equipment and manuals, warding charms and protective clothes, ancient tools and body paints. Maybe even creepy skulls and newt juice. Perhaps just the weight of malign knowledge or the pain of an ontogenic nanite injection.
The burden isn’t used up during casting. It can be stored elsewhere, but a hero can’t cast a spell that is not in their inventory. Some rare tomes are valuable solely because they let a hero carry multiple spells in a single inventory slot.
Common Spell Modifiers
Some spells are designed with mechanical quirks that change how they function. As players create their own spells, they are encouraged to invent and develop new mechanics of their own. If something doesn’t work well in play it can always be changed later. When a spell’s modifier has no special rules they can be marked with just a tag.
Anchor • The spell creates a physical anchor, which the caster stores in their inventory to keep the spell active and controlled. Destroying or losing the anchor ends the spell (or worse).
Attack • The spell is cast as an attack action. A caster uses their relevant magical skill to test against their foe’s defence and affect them. If a spell targets other attributes than defence, this is usually spelt out.
Dangerous • The spell forces a test to avoid magical corruption every time it is cast. Applying this mod to more spells is an easy way to restrict certain kinds of magic within a setting.
Focus • The spell requires focus to stay active. A caster must spend an action every turn, or the spell ends. A caster can always pay double the spell price to imbue the spell with their vital essence, keeping it active without focus. This is usually dangerous and requires a test against magical corruption.
Imbue • The caster keeps an imbued spell active so long as they reserve the vital essence (life or stat) spent casting the spell. Reserved essence reduces the caster’s maximum life or stat and cannot be recovered until the spell ends.
Item • When a caster creates a magic item, they use the spell to lock their existential force (life or stat) within a physical object. Locked force reduces the caster’s maximum life or stat and can only be recovered when the magic item is disenchanted or destroyed. This is similar to the imbue tag, except a hero cannot end the spell at will—they have to disenchant the item. Simple examples of magic items are magic swords, rings, and wands.
Regular • A spell that uses only the standard magic rules.
Casting Parameters
Casting any spell can involve all kinds of procedures. Individual spells attempt to specaify how they are cast, but magic, by its nature, creates edge cases in play. Players will have to interpret results that make sense to them, with the top cat sometimes exercising their power of arbitration.
Casting Time • Unless otherwise specified, a caster takes one action to cast a spell. Characters usually cannot cast spells with casting times longer than a round (however long it is) in the heat of conflict.
Ending A Spell • Casters can end most spells without an action. Disenchanting a magic item always requires at least one action.
Spell Durations • Spells are instantaneous in effect unless otherwise specified. Most durations are specified in real-world units of time or rounds. Some spells last until a condition is met (e.g. until the next sunrise, until the door is opened). When a spell’s duration runs out it fades away with a mildly hallucinatory dissonance.
Spell Ranges • Spell ranges and areas of effect may be phrased in the abstract, using zones of action (here, near, there), or real-world units. Spells with a range of self, zero, or nil can only affect the caster. Those described as having a melee, touch, or adjacent range can only affect targets the caster can or could reach with a limb.
Targets
A spell affects all creatures and objects in its area of effect unless otherwise specified. When a caster targets an unwilling creature, they must succeed at a relevant test for the spell to take effect. In conflicts, this is usually a test against the target’s appropriate defence. As with any attack, if a target is bound or restrained, no test is required, e.g., a vampire bound in silver or a xenophorm [sic] safely embedded in an artificial chest.
Adjudicating Spells
When the TC is unsure how many targets a spell strikes or how far its effects reach, they should use dice as oracles. For example, with a fireball they might declare, “it strikes the baker’s dozen of goblins. Roll 2d8 to determine how many are within its blast radius.”
If the targets were tightly packed, the number might double. If keeping their distance from one another, the number affected might be rolled with [-]. If the targets were tiny, a fireball might engulf more of them, while a storm of daggers would injure fewer. If they were huge, the effects might be reversed.
It’s usually better to find a quick answer with dice than to spend time calcu-lating a precise answer. Consistency is good, but playtime is more precious.
Hacking Spells
When a hero doesn’t have a relevant veda skill but has another skill that could potentially (with some creativity) also be used to cast a spell, they can hack the spell. This involves spending 2d4 weeks of game time tinkering with the spell, then a hard thought test to successfully adapt the spell to their skillset. A relevant trait, like fool’s luck, may apply.
d20 • Spell Hacking Test
1 • Hero fails miserably and will never succeed. Gains 1 mutation.
2–3 • Hero fails laughably, cannot try again. Test against corruption.
4–7 • Hero fails. Easy test against corruption.
8–11 • Failure and trivial test against corruption.
12–15 • Partial failure. [+] to next spell hacking test.
16+ • Success! Hero has hacked the spell and adapted it to work with their existing fantascientific skills! Player describes and names their novel spell variant.
When a hero successfully hacks a spell, their runner narrates how it works and how they have modified it. Every other player then suggests a quirk of the hacked spell. The hero’s player chooses the best quirk (using popular acclaim as a guide) and writes down the new, modified spell.
The player may name the hacked spell after their hero.
And Now: A Teaser Spell Album

Keen for more? Because you suspect I’ll continue to be terrible at updating this blog? Yes? Well, ok, that’s legit. Here:

Thank you, heroes,
for the cookies.
of the stratometaship
.