Sacred Underworld is an add-on for Sacred and requires the base game or Sacred Plus to play. A character that has at least reached level 25 is needed, but it is also possible to choose from the predefined level 25 characters that come with the game.
The kingdom of Ancaria is facing a new threat following the events of Sacred. Players have access to two all-new characters besides the six in the original game: the dwarf and the daemon. The former uses more conventional weapons like a flamethrower or a musket and has the ability to plant mines, which is very useful in multiplayer.
The latter actually consists out of three different characters: the battle, soaring and fire daemon. Each version has its own attacks, benefits and disadvantages and can be activated with one click. The soaring aura, for example, makes the daemon fly for a short period of time.
In the German version the player can meet a merchant named "Mick der Schnelle". He was implemented after Mick Schnelle, reviewer of German gaming magazine GameStar, complained about a lack of merchants in the beta version.