- If the enemy does not know you're attacking, he does an awareness check.
- If he fails that check (gets 3 or less) you attack first and he gets no chance to react.
The only exceptions are mental attacks and black holes. The other always gets a chance to mentally defend himself from mental attacks, but never gets the chance to act first if he is unaware. The other does a strength check to prevent himself from being sucked in black holes if possible (ie if somebody hasn't exploded an unavoidable vacuum cluster bomb around them).
Magical defenses are usually unaffected by whether or not he is aware of your attack. - If he succeeds, the battle continues normally.
If the player has not given an "in case I'm attacked" action with his post or PM, piecewise will choose an appropriate non-magical action for him.
- You both roll speed to determine who acts first. The one who rolls higher attacks first.
However if you both roll lower than 3, you stand still and do not act. - If both speeds are equal, both act simultaneously.
- A player can choose to forgo an action and instead try to run away. If he rolls higher then his opponent in speed and higher than 3 he successfully escapes.
- A player can choose to move out of melee range if he is in melee range. This doesn't stop the player from performing other actions that turn. The other can return to melee range if possible (ie if the player has not flied out of reach) during his counterattack.
- The player who rolls highest makes all the necessary rolls for his action (potency for spells, dexterity for aiming, strength for drawing bows and using melee weapons, etc.).
- If the other is aware of the attack he will try to dodge, parry, block or otherwise react non-magically and (usually) non-offensively.
- If the other is hit, unless there are special conditions, he also gets an endurance roll to determine the amount of damage dealt.
- If the other has not been stunned, killed or been otherwise incapacitated he will try to counterattack.
(There are some special conditions about damage when blocking, stunning and success when parrying but I don't remember those too well since I play a pure mage character and I am thus unlikely to engage in melee and survive.
You must also remember that certain weapons give +1s and -1s for certain stats and that armor can reduce the effects of hits if that is reasonable (wood can't stop lightsabers last time I chcked) however armor can reduce your mobility (speed).)