The Continuum, the main spanner civilization, extends through the whole of human history (and beyond, although the post-Human society of the enigmatic “Inheritors” borders on both sides). A primary focus of this civilization is to increase the knowledge and acceptance of time travel by the human race, so that when time travel is discovered and announced (approx. 2222 AD), humans will be ready for it, and moving into the next step in their evolution (becoming Inheritors). Another focus of the Continuum is the complete documentation of history.
The Continuum civilization also has “time criminals”, called “Narcissists”, so called because they seek to remake history in their own image. (In the late 1990s the publisher announced they would be releasing a version of the C°ntinuum book with the background material retold from the Narcissist standpoint. As of 2015, it has not been released, but a pre-release edition circulated in 1999 and 2000.1) The Continuum has members trained to “repair” damage caused to the course of history by the Narcissists.
The game’s solution to the issue of time travel paradox is the concept of frag. The universe does not tolerate paradox caused by time travelers, nor are parallel worlds created by paradox. Instead the universe begins to “erase” those for whom the paradox exists. (The frag concept appears to be based partly on the ideas in Alfred Bester’s “The Men Who Murdered Mohammed”.) Too much trying to change history (too much frag) and time travelers become something not quite real anymore. Frag can also be generated on purpose, a tactic in “time combat”. The Continuum society is partially built upon the repair of paradoxes that affect its members.
To explain frag by example, using the Grandfather paradox, a Narcissist might decide to travel back in time and kill his grandfather. If he “succeeded”, he would return to his own time to find his grandfather alive. (The Continuum would step in to “repair” the murder.) The Narcissist would then begin to fade out of existence due to the conflict between his own memories and actual history. He has been “fragged”.