Your journey in Ashen begins with the reclamation of a settlement, where you and your trusty companion can begin work restoring the Ashen to its former glory. As you explore the game world, you'll encounter a large cast of characters that each have their own missions and motivations. Once you have made them happy, they'll return to your settlement and begin to add to it, bringing their own skills and facilities to your base such as crafting, and fast travel, all while building up their own homes. By the end of the game, you should have a sprawling, and hearty village to call home. Each quest you do, whether as part of the main story or one of the more light-hearted side missions will also grant bonuses to your health and stamina pool, granting you new gear as you progress to the end of your ultimate goal. But the road to get there is filled with danger.
Ashen retains its headline feature, (almost always) anonymous asynchronous co-op, which is required to enter certain areas and dungeons. This co-operative play forms an important part of Ashen's uniqueness, since you won't be able to communicate directly (or often, even know) who you are playing with. That said, you will be able to play with friends using Ashen's filter system, which lets you set up a pass key for your game, effectively enabling pools of players to randomly appear in each other's games sharing the same key. In theory you could play co-operatively with a single friend this way, sharing the same pass key.
Those players will appear in your game completely dynamically, and anonymously, as you approach an area that requires a second player. If there is nobody available (or you disable multiplayer completely), a smart A.I. companion will spawn instead. And it is indeed smart.