When paradox is cast, the chronomancer can alter a minor event from his past that may affect the present. Such an event might be exchanging one memorized spell for a more useful one, having bought a cask of ale instead of a cask of oil, or deciding that, instead of insulting the ores' chieftain (who has been harboring a grudge, and now the characters need his help), the heroes insulted their finest warrior.
The event to be changed should not be more than three hours in duration, and it must be something that was personally done by the chronomancer, or something the chronomancer could have influenced. (Perhaps a thief actually made the insult, and the chronomancer uses paradox to explain it away at the expense of the orc warrior.) Something is always given up when this spell is used. The chronomancer can change an event as far back as one month.
The DM decides how the change proceeds forward, if at all. Often, things will not work out as neatly as the caster might hope. The orc chieftain could still bear a grudge (that the warrior was insulted), and the warrior might wish now for personal satisfaction.
Notes: Restricted to chronomancers; common.