The id universe (there may not be an official name for the idea) is a concept associated with the Id universe timeline, which interprets that all of the original Wolfenstein games (and up to Return to Castle Wolfenstein, and possibly Wolfenstein (2009)), the various ID phone RPG game series, Doom 1/2/3/4, Quake/2/3, and Commander Keen (and maybe others) are all part of the same universe, but at different points in history. It explains that many of the series characters are related somehow often through the Blazkowicz family line (this was first introduced with Doom RPG and its website which confirmed that the character (B.J. Blazkowicz in Doom RPG, is the same marine in Doom, Doom II, and Doom 3).
Originally at least Wolfenstein and Commander Keen have been connected through lore introduced in the hint guides for Wolfenstein and Spear of Destiny. But Doom RPG, and later Wolfenstein RPG took this much further.
This universe is alternative to, and completely incompatible with the Old Blood/New Order timeline. Which is set in an alternate universe.
- ↑ you reprise the role of the Doom Marine made famous in the groundbreaking id Software titles Doom, Doom II, and Doom 3."http://web.archive.org/web/20060104031037/http://www.doomrpg.com/n.x/Doom%20RPG/Home