
- BGG rank
- BGG #4,968
- BGG rating
- 7.6
KeyForge: Dark Tidings
- 2 players
- 15–45 min
- Complexity 2.8/5
- 2021

2020
Rules assistance for KeyForge: Mass Mutation
Plain-language explanations of turns, card effects and disputed situations, with official source references and saved question history.
For 2 players

What would you like to know?
Answers come from the official rulebook, with the page to check.
KeyForge: Mass Mutation is a board game released in 2020 for 2 players, 15–45 minutes per game, and ages 14 and up. It was designed by Richard Garfield, Brad Andres, Aaron Haltom, and Daniel Schaefer and its main mechanics are Hand Management and Take That.
Change is coming to the Crucible with the Mass Mutation set for the world’s only Unique Deck Game, KeyForge. Over 200 brand-new cards now enter the cardpool in the game’s fourth set, and the mutative power of the dark æmber has changed many of them, creating strange and unknown versions of once-familiar creatures. As gigantic creatures stretching across two cards lumber their way into battle, and House Sanctum makes its triumphant return, there has never been a more impactful time to leap into the fast-paced duels of KeyForge. Each Mass Mutation Two-Player Starter Set contains two ready-to-play 36-card decks, bringing together three of the diverse Houses of the Crucible—each featuring their own mix of cards and unique from every other Archon Deck in existence. You’ll also find all of the tokens that you need for two players to start playing KeyForge! —description from the publisher
KeyForge: Mass Mutation supports 2 players according to the catalogue. This is the publisher’s listed player count, so the game is designed for exactly that number of participants. Variants for other group sizes, if any, are described in the rulebook of your edition, so check it before setting up a different configuration.
The listed playing time for KeyForge: Mass Mutation is 15–45 minutes. This is the publisher’s estimate for a full game. The actual duration depends on the group, the player count and familiarity with the rules: first sessions usually run longer, while experienced groups often finish faster. Setup and teaching time are not included in this estimate.
The catalogue lists KeyForge: Mass Mutation for ages 14 and up. This is the publisher’s recommendation and reflects reading demands, rule complexity and small components rather than theme alone. Younger players can often join with help from an adult, so check the age guidance on your edition and consider your group’s experience with board games.
KeyForge: Mass Mutation has a complexity rating of 2.8 out of 5 from BoardGameGeek players, which makes it a medium-light game. The rating reflects how much rules knowledge, planning and decision-making a typical game demands. Expect a longer first teach for heavier games, and use a preparation guide before game night.
KeyForge: Mass Mutation belongs to these categories: Card Game, Fantasy, and Fighting. Its main mechanics are Hand Management and Take That. Categories describe the theme and setting of a game, while mechanics describe what players actually do on their turns. Each mechanic links to a catalogue hub with similar games, which helps when you want something comparable.
The credited designers of KeyForge: Mass Mutation are: Richard Garfield, Brad Andres, Aaron Haltom, and Daniel Schaefer. These credits come from the published game data and name the people responsible for the game’s design, not its illustrators or publishers. Designer pages on MeepleRules collect other titles by the same designers, which helps when you enjoy a game and want to find similar ones.
The catalogue lists KeyForge: Mass Mutation as a base game. It can be played on its own with the components in the box and does not require any other title. Expansions, if any exist, add new content or rules on top of it and are listed separately in the catalogue with a link back to this base game.