EUO is an Ultima-based online RPG with many influences, varying from Diablo-style hack'n'slash to NetHack quirks. It is closely tied to the Origin Ultima V RPG.

Created originally by eggmceye to be a rogue-like game named Balrog in 1998, it was quickly turned into an Ultima-like game with the discovery of an Ultima 4 tileset created by Josh Steele, giving the game its retro feel. Over the past nine years, it has slowly evolved into an online RPG with a small but growing fanbase spanning two servers, each one incorporating slighty different gameplay.

In those nine years, the game has grown from a four player only server to one that incorporates a full Ultima V magic system, including the Runic alphabet, crafting and creature taming. It also contains numerous easter eggs in tribute to NetHack.