A chaotic limiter was used to regulate the causalness of a time traveller.
Low settings meant the individual had little impact on the era they were visiting, high settings the reverse. For example, deploying a high yield nuclear bomb on a low setting and treading on a butterfly on a high setting would have roughly the same effect.
An upper limit was never discovered. Fluxes were created using extremely high settings, and conceptual entities could be made with modified limiters. (PROSE: The Book of the War)
It is possible that the limiter manipulates reality quotients. (PROSE: The Crystal Bucephalus)