So You Wanna Design a Spell

So You Wanna Design a Spell...
'I cast magic missile!'

— Any gamer who has ever played a magic-user/mage/wizard/sorcerer

This document covers how to design spells in the d20 system. Before we begin, it's important to keep in mind what this document is and what it is not.

This Paper Is...

A simple guide to the basics of spell creation and presentation.
A reference you can use to help get you started in spell creation.
Intended to help you format spells in accordance with a reverse engineered analysis of WotC's house style.

This Paper Is Not...

A mechanical analysis of the d20 magic system
A tool for producing mathematically balanced spells.
Designed to teach you how to build the guts behind a spell.

In essence, after reading this document you should have the tools needed to write a spell that obeys d20 system conventions in terms of WotC's presentation of spells. It includes tips and pointers to useful spell design resources contained in the three core books, but it is not meant to cover the nuts and bolts of designing spell effects.

This Paper is Meant For...

Current or would-be freelancers who want to present spells they design in WotC's standard form.
DMs who want to create new spells within established d20 system conventions.
Laymen curious to see the grunt work behind putting together a spell.

Presenting Spells

If you own a PHB, you've noticed that almost half the book is taken up with spell descriptions. The first step to putting together a spell is to present it in a format that follows the standard D&D conventions. Since the PHB gives us so many examples, it shouldn't be a hassle to look it over and figure out what the standard presentation looks like. Here's a worksheet I use to help make it easier to write up a spell.

Here's the template, with sections bolded as per the PHB. After each section is a short commentary in red discussing how to fill in that piece.

You can download an RTF file of the template without the commentary here. Use this as a worksheet when designing spells.

Pre-Flight Check List

Step Zero. Read chapter 10 of the PHB 3.0. It covers all the basics of how spells work in the d20 system.

Step One. Find a spell that has a similar effect as the spell you want to create. For example, if you want to design a spell that produces a cone of fire, check out cone of cold and use that as a basis for the system bits.

Step Two. Page 171 of the PHB 3.0 has a complete overview of the spell format. Use that as a guide as you go through and design a spell. It also quite handily includes page references that point to explanations of spell ranges, durations, and so on.

Step Three. Page 95 of the DMG 3.0 has notes on designing new spells. They aren't exhaustive, but they are a start.

Step Four. Always italicize spell names. DO NOT CAPITALIZE THEM UNLESS A PROPER NAME IS PART OF THE SPELL'S NAME. Yes, I have issues with this. Far too many people randomly capitalize spell names (and prestige class names, monsters, weapons, etc, etc, ad nauseum.) It's annoying as heck to edit.

Step Five. These guidelines are not holy writ. They have served me great over the years, but some publishers have house styles they use in presenting d20 material. Check with your editor before keeping with the guidelines presented here.

Spell Name

Try to give a spell a descriptive name. Fireball is the classic spell name. It creates a big ball of fire. If you want to include the spell's creator in the name ("Mearls's Fabulous French Fry Summoner") do a Google search to make sure the cool sounding moniker you want to use isn't the name of an 80's metal band, a South American city, or anything else that'll make readers laugh at you.

School (School Subtype) [Descriptors]

WARNING! Everyone screws this up. Read pages 156 - 157 of the 3.0 PHB. This'll give you an overview of the schools and subtypes. Page 171 lists all the descriptors. Do not simply make one up.

Level: Brd X, Clr X, Drd X, Pal X, Rgr X, Sor/Wiz X

X is the spell's level. Obviously, delete classes that don't have access to the spell.

Components: V, S, M, F, DF, XP

These are all explained on page 171 of the 3.0 PHB.

Casting Time: 1 action, 1 round, etc

Range: Personal, Touch, Close (25 ft. + 5 ft./2 levels), Medium (100 ft. + 10 ft./level), Long (400 ft. + 40 ft./level), Unlimited, or Other

Target or Effects or Area (pick 1): See spell descriptions for examples

Duration: See duration, p. 150 of the PHB 3.0.

Saving Throw: Fortitude, Reflex, or Will negates or partial (harmless)

Spell Resistance: Yes or No (harmless)

Error Alert! Many people mistakenly fail to ascribe saves or SR checks to helpful spells. These spells still have this info, but they are marked as (harmless). Check out bull's strength for an example.

Descriptive text here. Describe effects of spell in plain English in the first paragraph of the spell.

Describe rules that apply to spell in the second paragraph.

Write in second person. "You create a ball of twine that spins around the room, dealing xd4 points of damage."

Add any component costs at the very end, like this:

This spell causes sheep to turn green.

Arcane Focus or Divine Focus or Focus: A can of green spray paint.

Material Component: A quantity of paint from a can of green spray paint.

XP Cost: $500 fine and a night in jail.