Where are the rules for combat fatigue?
There are none. Earlier editions of Ars Magica called on players to make Fatigue rolls for their characters at specified points in battle – depending on the edition, either every round or every time the character changed weapons or opponents. The combat-fatigue roll seems to have been generally considered more bookkeeping than it was worth and is gone from ArM5. Characters in combat are very likely to lose Fatigue levels anyway, by spending them voluntarily under the “exertion” option (p. 173). The storyguide can always call for extra Fatigue rolls in battle under unusual circumstances, for instance, if it goes on for an exceptionally long time.
