Magic System
Every author writing fiction with structured rules eventually hits the same problem. You’ve decided your magic has a cost. You’ve decided your hero’s power level caps somewhere. You’ve decided a wound in chapter three limits what a character can do in chapter eight. And now you’re on your twelfth scene in that magic system and you’re starting to forget what the rules actually are — which means your prose is starting to bend them without you noticing, which means your beta readers are about to tell you that your hero’s power level is inconsistent, which means you’re about to rewrite three chapters to make the rules hold.
The Magic System module is where those rules live so they stop slipping.
Despite the name, it’s not just for magic. It’s for any fiction with structured constraints. Soft magic systems. Hard magic systems. Superhero power levels. Cultivation tiers. Cyberware load. Spell slots. Dice pools. Stamina drains. TTRPG character sheets. Sanctioned abilities in a courtroom drama. If your fiction says “this character can do X but not Y, for these specific reasons,” the Magic System module is where X and Y get defined, assigned to characters, and checked against your prose.
This page is the brief overview — what the feature is for and how it fits into the Legendry. The full reference, with ruleset design, stat blocks, formulas, abilities, probability analysis, and the RulesLawyer agent, lives in the dedicated Magic System section below.
What it gives you
Section titled “What it gives you”- Rulesets — A named container for all the stats, formulas, and abilities your project uses. A project can have multiple rulesets but only one is active at a time. Perfect when you have a main novel universe and a side prequel that uses a stripped-down version of the same rules.
- Stats — The fundamental numbers your fiction tracks. Strength, Intelligence, Mana Capacity, Cultivation Tier, Cyberware Load, Taint — whatever your system needs. Integer, float, or dice step. Min, max, default. A name and a category.
- Formulas — Derived values computed from stats.
floor((strength - 10) / 2)for a D&D-style ability modifier.base_hp + (constitution * level)for a scaled health pool. Dice notation for randomized systems. Circular reference detection so you don’t break the math. - Abilities and modifiers — Spells, powers, techniques, feats, traits. Each one has its own cost, duration, effects, prerequisites. Attach them to characters and the stat block shows which abilities they can currently use.
- Stat blocks on lore entries — Every character, creature, item, or any other lore entry can have a stat block. Base values plus modifiers plus formulas equal effective values, computed automatically.
- Presets — D&D 5e, Pathfinder 2e, and Fate Core ship as built-in starting points. Import one if you’re writing in an established system, customize it, or ignore them entirely and build your own.
- Probability analysis — If your system uses dice, Ishvana can compute exact probability distributions, power curves, and opposed-roll margins. For authors writing in established TTRPG systems, this is the fastest way to check whether a fight you just wrote is actually balanced.
- RulesLawyer — An agent that reads your prose and flags places where it contradicts the Magic System rules. “The character is described as weak but has Strength 20.” “This spell was cast at cost 5, but the ruleset says it costs 10.” The agent runs on demand — it’s not a real-time annotation layer.
- Character Sheet Designer integration — Stat blocks feed the Character Sheet Designer. Design a character sheet layout for your system, link it to a lore entry, and the sheet reads and writes the underlying stat block. TTRPG authors can print actual sheets from their Legendry.
Why the name was changed
Section titled “Why the name was changed”An earlier version of Ishvana called this feature “Mechanics.” That name came out of TTRPG terminology, and in practice it made fantasy authors who weren’t building TTRPGs feel like the feature wasn’t for them. It is. “Magic System” is broader — writers of every kind of speculative fiction use it, because every kind of speculative fiction has structured rules somewhere, even if those rules aren’t written down as dice mechanics.
TTRPG authors aren’t left out. The full Magic System section includes a TTRPG usage guide that explains how to use Ishvana as a game design tool, including campaign setting books like Welcome to Tikor.