Released in 2005, Sacred Underworld is an expansion pack for the 2004 game Sacred, developed by Studio II Software and Ascaron Entertainment. It uses the same formula as Diablo: first hack, then slash, grab the loot, spend skill points, and save the world. However, it has a unique storyline about an unlucky necromancer who sets free a giant demon, a freely explorable continent instead of randomly generated areas, two single-player campaigns, and seven character classes including dwarves, angels, demons, vampires, and elves. One thing Sacred is famous for is its crazy easter eggs and funny references to other games, like the BFG from Doom. The game is also famous for its bad controls and horrible bugs, which prevented it from receiving the appreciation it deserved.