Searching through kickstarter i found this interesting diablo III / D&D mix. Its for PC / MAC (Unsure for Linux OS). Its a game where the community creates the majority of the content and can play it. It looks very promising, i'll link the page and the information i've found.

Dungeonforge is an Action-RPG in the spirit of classic D&D where you, as dungeon master, drive and shape the gameworld and everyone has a chance to weave their unique part of gaming lore.

In Dungeonforge all the action takes place in a massive, open gameworld. This world is your canvas; the place where you will tell your story as a dungeon master.Through our in-game editor which we've termed "the Dungeonforge," you will be able to craft adventures rife with deep dungeons, dark woods, frosty mountain tops, and just crawling with the unspeakable legions of darkness. Your content then becomes part of the over-arching gameworld for all to enjoy. You can script quests within your adventure for players to complete, or even perform a "Live Telling" of your adventure, wherein you actively take the role of dungeon master, playing the part of NPCs, weaving dialog on the fly, and controlling monsters to shape the experience of the players dynamically, in real time. Going further along that theme, we will also feature a competitive, PvDM game type, which will pit the players against the DM, who will be given charge of the hordes of evil in an attempt to thwart the players on their quest.

Link

https://www.kickstarter.com/projects/1004444231/dungeonforge-be-the-ultimate-dungeon-master