Where are the rules for making an all-out attack or defense?
This is covered by the Exertion option on p. 173. There are no rules for simply borrowing points from your Attack and putting them into Defense, or vice versa. That was an option in earlier editions of Ars Magica but it seems to have been intentionally dropped. Many people seem find the new exertion option more playable. It gives flexibility but it is unlikely to be over-used because it costs a Fatigue level – a very scarce resource in combat. A house rule re-introducing an all-out attack option might lead to balance problems, especially if you allow it to be combined with exertion. In Ars Magica, the outcome of a battle can be decided by the first significant wound, so allowing too many Attack bonuses to stack up would give a large tactical advantage to whoever gets to attack first.
