Simultaneous Rounds
Simultaneous Rounds is the most common combat system. The scene is broken up into discrete rounds. Each round, every fighting character makes an opposed roll against his or her opponent. The winner’s relative degree determines the damage. This system assumes that attack and defense are combined in a single trait.
If a character is fighting more than one opponent, the lone fighter’s result is compared to each opponent, one at a time. He must match or exceed all of them to score a hit. Any opponent who exceeds the solo fighter’s result scores a hit.

Blow by Blow
Blow by Blow combat, also called Alternating Rounds, is a more typical RPG combat mechanic. Each round, every combatant gets one attack. Each attack is an opposed roll. If the defender wins, the attack missed. If the attacker wins, the blow is resolved just as in simultaneous rounds. And all actions are in effect at the end of the round. Thus they technically happen simultaneously but not resolved that way.

Either of these systems can be used in the Teara Adan Adventures world.

Combat Procedure

1) The GM sets the Difficulty Level and whether the roll is unopposed or opposed. The base Difficulty Level for melee combat is Poor. For ranged combat the Difficulty Level is determined by the range from the target. Other situational factors can apply to both melee and ranged combat Difficulty Levels.

2) Skill rolls are made and the relative degree is determined.

3) If the Difficulty Level is made whoever won the relative degree gets to possibly inflict damage on the other. This base damage is determined by taking the Relative Degree and adding in the ODF and then subtracting the DDF.

4) Base damage is modified using a 4dF roll with the following restrictions:

If the base damage is positive the roll cannot be more than the base damage.
If the base damage is positive the roll cannot modify it to be less than +1.
If the base damage is negative the roll cannot modify it greater than +1.

Aim at specific Body Part/Called Shot: Good or Very Good Difficulty and -1 to the Skill
All-out Offense: +1 to Combat and +1 to Damage. If the attack fails the attacker receives +2 Damage
All-out Defense: +2 to Combat but only deals damage on a +4 result.