Grit d20

This game was written for TTRPG Crossover Jam 2026.

Hypothesis and effects

Because the Grit System is far less wild in range than the d20 system, adding a d20 to everything will make our games more random feeling—both more "epic" in a fun way and more chaotic in a challenging-to-plan-for and challenging-to-interpret way.

That said, why not? People love their math rocks. Go throw em!

Specifically, adding a d20 to damage results using weapons (not unarmed attacks) makes combat deadlier. This change should be fun (though it requires more simple addition) and is a major reason to try Grit 20.

Also included: some thoughts on the Weird ("magick"). I added wild magic and even included "legendary warding" (boss saves) in hopes of sufficiently crisscrossing the systems.

Design choices and opportunities

I chose an A6 format because it's charming. I used my own old sketches because I made this in a hurry.

In the future, if this system proves fun, someone should add rules for classes that embrace the math rock.

Obviously, rolling a nat 20 deserves a full spread of critical fun.

Caveats and invitations

I have not playtested this hack yet (beyond some solo dice-rolling), because I wrote it for a jam. If you like d20 games and are new to Grit System games, try this hack and let us know what you think on the Stillfleet Studio Discord.

In fact, at the time of publication, we are running the first-ever Grit System Game Jam. If anyone is interested in extending, re-hacking, or counter-hacking (?) this quick jam entry, please be my guest! Check out our third-party licensing  via the jam page.

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Grit d20
Version 1.0 ☉ June, 2026
Created by Wythe Marschall (writing, art, layout)

© 2026 Wythe Marschall