During a battle, an attack made by a player character occurs in 2 steps: an attack roll and then damage calculation.
Attack Roll
The attack roll is used to determine if the attack action fails or succeeds when the player character makes an unarmed attack, uses a weapon, or employs an offensive ability.
This attack roll is determined by rolling a 20-sided die (D20), to which a characteristic modifier and the character's level are added.
The characteristic modifier and the type of attack to consider are indicated by the weapon or ability used.
The obtained score is then compared to the opponent's physical defense (Def PHY) or magical defense (Def MAG) based on the type of attack performed: physical (Atq PHY) or magical (Atq MAG).
Physical attacks (Atk PHY) include melee attacks (Atk Melee) or ranged attacks (Atk Ranged).
Attack Roll = D20 + Character Level + Characteristic.
Possible bonuses may be added to the attack test result, specified by the weapon used or by certain abilities (or both).
Example :
Sword STR+1 DM 1d6+1 during the attack test with this weapon you will have to add your Strength (STR) as well as the value 1.
Atk Roll = D20 + Char. Level + (STR+1)
Damage
If the attack roll succeeds, the player character can then determine the damage inflicted on the opponent. These damages are determined by the weapon or ability used (or both).
Example :
Sword STR+1 DM 1d6+1 to calculate damage, roll 1d6 and add 1 to the result.