A DLC called Dark Sorcery was announced at the Legends of Aria site. It will already be released later this month at 19.99$ and is available for pre-order now.
The theme of the DLC looks dark and Lovecraftian by the art posted on the site.
The DLC will add a new dungeon called the Monolith, new enemies, skills, and loot.
By pre-ordering the DLC you will also get the Dark Echo Fox Mount.