As requested by a fan of Evil Hat Productions, here is some information on running a Mouse Guard game using the Fate system. TL;DR: My thinking process, followed by lots of useful links at the bottom of the post.
When I was in the final stages of writing War of Ashes: Fate of Agaptus for Evil Hat Productions, I wanted to test the rules we had grafted onto Fate Accelerated to support the use of miniatures. I wanted to check whether they would play well when used in another setting and handled by a game-master who wasn’t part of the development team. My friend Kit was nice enough to run it for us using the setting from the Mouse Guard RPG (Archaia Studio/Burning Wheel Games) and the episode was a success. I later ran it a few times at conventions and it was great fun.
Recently someone (Tim R.) wrote to Evil Hat to ask how we made these adaptions. I never posted any notes before because in truth, this was not a full-fledged conversion. However, the Fate Accelerated engine is excellent for conversions-on-the-fly! And I think the miniatures rules we came up with work very well with otther settings, especially fantasy settings.
I use the rules for War of Ashes pretty much unchanged in play, particularly the rules for advanced conflict. (I do not use the Fickle Gods rules, as this does not fit the Mouse Guard setting, but the Lost Civilization rules would be usable.)
The one thing that is different is that I obviously can’t use the Agaptus-related character creation steps, such as faction aspects and faction stunts; I do however use the expanded stunts. To make Fate of the Mouse Guard player characters, I use the information from the Mouse Guard RPG to inspire aspects and stunts. For example, a guard mouse might have aspects related to their mentor or family, or to their beliefs and goals.
- Pick a high concept, a flaw, and one to three starting aspects inspired by the elements of the Mouse Guard RPG.
- Pick your approaches.
- Pick one to three starting stunts, including equipment stunts in you want.
- Your Refresh is 3.
- You have three stress boxes and can take one mild, one moderate, and one severe consequence.
- Pick reasonable and appropriate gear, just like in the Mouse Guard RPG.
- Pick a name, cloak colour, and description (there are useful suggestions in the Mouse Guard RPG.)
When Kit ran the game, she helped focus aspect creation by writing prompts on index cards and having us draw a few each at random. They were either questions like: “Why does the mouse Benjax keep getting off the hook when he’s arrested?” or statements like “A history with weasels.” We each picked up a couple of the cards that spoke to us and made aspects off of them, such as:
- “I shot the Sheriff of Goldblossom.”
- “My brother the Mail Mouse is missing!”
- “Coal thinks he’s above the law. He isn’t!”
- “Benjax won’t get away… again!”
- “I stabbed Rostov the Weasel. He saved my life.”
This worked really well and is particularly suited to one-off games, such as convention events.
To write scenarios, I use the adventure creation rules. I pick the environmental aspects for individual scenes using inspiration from the description of seasons in Mouse Guard RPG. Similarly, I figure out what my NPCs and critters are good at and bad at by looking at their description in Mouse Guard, and their stats by comparing to various creatures and characters in War of Ashes and scaling appropriately. You can see the results in the one adventure I was able to find in my old notes (Google Docs file.)
Resources
Mouse Guard
- David Petersen’s official Mouse Guard site offers lots of free resources on the setting.
- The Mouse Guard RPG by Luke Crane and David Petersen is a must, you’ll find all the background you need for a campaign. I have the first edition hardback, but there is a second edition hardback and box set too.
- The Mouse Guard collected graphic novels, also available from the official site, have lots of useful background material on the setting in the appendices.
Fate and War of Ashes
- War of Ashes: Fate of Agaptus (Evil Hat Productions) is available in electronic format or hardcover book. Forgive me for tooting my own horn, but I’m darn happy with this book. The PDF is currently available pay-what-you-want on DriveThruRPG.
- If you don’t have (or don’t want) War of Ashes, you can still play using Fate Accelerated (Evil Hat Productions, available in electronic format as a pay-what-you-want download or a $5 softcover book), plus the advanced conflict rules.
- The rules for Fate Accelerated and War of Ashes: Fate of Agaptus are also available free on the Amazing Rando’s super-useful Fate SRD site.
- The Fate of the Mouse Guard adventure I ran at the Dragonflight game convention in 2015: “The Missing Alchemist,” as a Google Doc file.
Mouse Miniatures
- ZombieSmith/Flytrap Factory (Netherworlds line)
- Reaper (Mouslings line)
- Plaid Hat Games (plastic figures from the Mice & Mystics game)
The Reef 
Thank you. Now that I have the book I would love to try this out.