Initiative is rolled at the beginning of combat like normal. Once turn order is established, each participant declares their intent from lowest to highest initiative, so that the highest Init character has the advantage of seeing what everyone else is trying to do. Actions are then taken from highest initiative to lowest, and each character must proceed with their declared intentions unless it has been rendered impossible by the actions previous (ie, attacking someone who has already been killed, or moving after they’ve been grappled). This process repeats every round.
Damage and Hit Points
Hit points are both a representation of a character’s endurance, luck, and physical condition. In general when a character receives non-subdual damage, he is not actually injured until he runs out of hit points. The loss of hit points represents dodging, blocking, or parrying an attack. When a character runs out of hit points he is actually injured.
An exception to this is critical hits. A critical hit ALWAYS physically injures a character if it does damage. The result of the injury is usually rolled on a dice, unless it was a called shot. (We use a special critical hit dice for this).
Because normal hits are not physical injury, it is not required to make Fortitude saves to survive massive damage regularly. If the character hit by damage equal to or greater than 1/2 of their hit points, and it was a critical hit or the damage would reduce the character to fewer than 1 hit point, then the character must make a Fort save at DC 10 + 1/2 the damage taken (rounded up). Failure results in immediate death.