Ashen, from Aurora44 and Annapurna Interactive, is an epic Action RPG where players must live in a world without a sun. It also has something called "passive multiplayer" where other players show up as NPCs from your game to help you on quests. If you don't have an internet connection, those same NPCs can help you. It's a pretty novel way to do an MMO that can feel like a solo game, we must say.
Check out the demo from Gamescom:
