How to write new abilities

I love seeing everybody cooking up new kiths, kins, talents, and other player-facing rules for His Majesty the Worm during the Worm Jam.

I wanted to offer a few guiding principles for how I think about writing player character abilities in OSRy games.

Talents should be active

Abilities that give you +1 to a stat or favor to some task aren’t very interesting. When you look down at your sheet, see the number recorded there, and apply it to your test–it’s just an amalgamation of numbers interacting with each other, not a cool representation of how your character’s abilities are impacting the world. I’ve written about this before in my post Making +1 Swords Feel Magical.

Instead, make abilities that players choose to use. To get favor on their attack, they need to cry their battle cry aloud. To use their colossal strength, they have to hulk out. And if there’s a constant bonus (you’re immune to poisons!), contrast it with a strange factor that makes it so the player can’t forget it (…because your nervous system is made up of fungus and you need to constantly eat new types of mushrooms or you’ll die).

No set-it-and-forget abilities! Make buttons for the players to push to activate their talents.

Talents should offer you new ways to approach problems

Each talent is a way to break the rules–the rules of the game and the rules of the world. As players accumulate abilities, they gain new tools in their toolbelt. The open-ended, deadly challenges of the Underworld should only be able to be solved through the judicious use of the weird tools the players have at their disposal: the floor is made of lava, but I can shimmy along the walls; the guard has the keys to our cell but I have a long sticky tongue that can grab them off of his belt; the freezing mist makes it difficult to fight the skeletons, but the wind owes me a favor so I’ll blow it away.

Don’t start with the mechanics; start with what you’re imagining the ability does in the fiction. Then figure out how to represent it using the rules of the game.

I think it’s fun to actually provide abilities that really let you break the rules (“I’m immune to damage! I can fly! I can phase through walls!”) as long as they’re temporary and have significant drawbacks (“…because I’m a ghost! I can’t touch anything! If I’m not back into my body by the end of the watch I die for real!”).

Relatedly, if an ability just duplicates the utility of having a tool, the usefulness is limited. Yeah, having hair that can be grown long as ropes sounds cool (…well, wait, that does sound pretty cool), but 9 times out of 10 you’ll be better off just bringing rope in your pack.

Talents should be unique

As much as possible, abilities should feel unique. Having four spells that are duplicates of each other, except each does a different type of elemental damage, is just a waste of page space.

Abilities that you choose during character creation are a way for a player to tacitly communicate with the GM: This is my kinda dude, and I wanna do these sorta things. I’m a fighter, I want to fight. I’m a sorcerer, give me an opportunity to use my spells. The uniqueness principle offers some niche protection to players. It feels lame when a wizard is better at stealing than the thief because they have spells like Knock, Invisibility, Audible Glamour, Sleep, etc.

Moreover, abilities that share a lot of surface area give rise to discussions about balance, which I cannot care less about. Abilities should be incomparable. Who can say whether it’s better to be able to fall long distances without being hurt versus being able to take on the shape of a mouse when you spend a Resolve? Both are useful in their own situations. One isn’t better than the other.

Talents shouldn’t negate an adventurer’s “general competence”

People have long said that the introduction of the Thief class is when D&D jumped the shark because it created a skill system that made the things that everybody should be doing (sneaking, climbing, listening) locked behind a single character class. (Trying to “fix” the Thief class is an OSR blog rite of passage.)

This is also the case of the “Breathing mermaid problem.” The Breathing mermaid problem describes a situation in RPGs where some character ability solves a problem you didn’t know you had. “With the Tracking feat, you can track.” Could I not before? Avoid rules that are defined by negation.

Adventurers are assumed to be competent. Every character can sneak, climb, listen at doors, hide in shadows, use rope, disarm foes, track game, etc. Abilities that change the expectation of what a competent person can do without a certain ability is a negative design pattern.

Talents shouldn’t overcome the essential dangers of the dungeon (light/darkness, hunger, resource scarcity, stress, equipment slots)

Perhaps most importantly, the back of the game book says that “Food, hunger, light, and inventory management are central to play and actually fun.” No ability should get rid of these essential threats. This is what the game is about! Abilities like “continual light” or “bag of holding” would reframe what His Majesty the Worm is all about as much as a spell called “Instantly Win: Spend a Resolve and you find your Quest and go home and the Worm dies.”

Two other posts about abilities that are “good” and “bad” for dungeon exploration games:

• Goblinpunch - Keep Dungeon Threats Threatening
• Udan Adan - Game Enhancing Powers and Game Ruining Powers

Homebrewing advice

Last, I’ll share the bit I have about homebrewing from the game:

By the way...

Did you know the Worm Jam is currently going on? It's a space for folks starting new games of His Majesty the Worm to collaborate with each other. Come join us!