Ultima Underworld: The Stygian Abyss is a first-person role-playing video game developed by Blue Sky Productions (later Looking Glass Studios) and published by Origin Systems. Released in March 1992, the game is set in the fantasy world of the Ultima series. It takes place inside the Great Stygian Abyss: a large cave system that contains the remnants of a failed utopian civilization. The player assumes the role of the Avatar—the Ultima series's protagonist—and attempts to find and rescue a baron's kidnapped daughter. Ultima Underworld has been cited as the first role-playing game to feature first-person action in a 3D environment, and it introduced technological innovations such as allowing the player to look up and down. Its design combines simulation elements with concepts from earlier role-playing video games, including Wizardry and Dungeon Master, which led the game's designers to call it a "dungeon simulation". As such, the game is non-linear and allows for emergent gameplay. Ultima Underworld sold nearly 500,000 units, and was placed on numerous hall of fame lists. It influenced game developers such as Bethesda Softworks and Valve, and it was an inspiration behind the games Deus Ex and BioShock. The game had a sequel, Ultima Underworld II: Labyrinth of Worlds (1993), and a new game in the series, Underworld Ascendant, was released in late 2018. Gameplay Ultima Underworld is a role-playing video game (RPG) that takes place from a first-person perspective in a three-dimensional environment. The player's goal is to adventure through a large, multi-level dungeon, in which the entire game is set. The player uses a freely movable mouse cursor to interact with the game's world, and with the icon-based interface on the heads-up display (HUD). Each icon has a specific effect; for example, the player uses the Look icon to examine objects closely, while the Fight icon causes the player character to ready their weapon. The player's progression through the game is non-linear: areas may be explored, and puzzles and quests finished, in any order. An automatically filling map, to which the player may add notes, records what the player has seen above a minimum level of brightness. The player character may carry light sources to extend the line of sight in varying amounts. Exploratory actions include looking up and down, jumping, and swimming. The player begins the game by creating a character, for whom traits such as gender, class and skills may be selected. Skills