Ironsworn is a tabletop roleplaying game that is designed to be played solo, co-op, or traditionally with one or more players and a gamemaster.
. . . you are a hero sworn to undertake perilous quests in the dark fantasy setting of the Ironlands. You will explore untracked wilds, fight desperate battles, forge bonds with isolated communities, and reveal the secrets of this harsh land.
Are you ready to swear iron vows and see them fulfilled—no matter the cost?
The game and its supplements are available to download for free, and is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike license (there’s even an Ironsworn System Reference Document for commercial works using the system).
Of course, there are also some beautiful looking print versions of the books available at DriveThruRPG.