Ultima Online (UO) is a fantasy massively multiplayer online role-playing game (MMORPG) released on September 24, 1997 by Origin Systems. Set in the Ultima universe, it is known for its extensive player versus player combat system. Since its release, it has added eight expansion packs, a booster pack and dozens of free content updates. The release of Ultima Online: Kingdom Reborn in 2007 brought a new game engine with upgraded visuals.