Backstab

Backstab (バックスタブ) is a stand-alone Jupiter Psynergy introduced in Golden Sun: The Lost Age.

Basic Characteristics
Backstab is an offensive, single-target Psynergy that is Attack-dependent, meaning that characters with higher Attack will deal more damage with this Psynergy. In addition, the caster's Jupiter Power and the target's Defense and Jupiter Resistance will all factor into the damage dealt.

Visually, Backstab features the user appearing behind the opponent and performing a standard physical attack. Afterwards, a large cluster of stars fire out of the targeted opponent.

Damage Calculations
Elemental physical attacks such as Backstab use the damage dealt by the attacker's standard physical attack as the base damage to be later modified. The total amount of damage dealt by a normal physical attack is half the difference between the attacker's Attack statistic and the target's Defense statistic, as this equation shows:


 * base damage = (User's Attack - Enemy's Defense) / 2

Backstab's attack takes this base damage value and uses it in the following equation:


 * final damage = (base damage + bonus damage) * (1 + (User's Jupiter Power - Enemy's Jupiter Resistance) / 400)

To word this in prose, Backstab takes the base damage of the user's normal physical attack, adds a set amount of bonus damage to that, and then this result is modified by how much higher or lower the user's Jupiter Power is than the target's Jupiter Resistance. The difference between the user's Jupiter Power and the target's Jupiter Resistance is divided by 400, then 1 is added to this, resulting in what can be called the "elemental damage multiplier". This number is what the Psynergies' damage is multiplied by.

For example, if an Adept with an Attack rating of 300 and a Jupiter Power of 150 casts Backstab on a monster with a defense of 100 and a Jupiter Resistance of 50:
 * damage = ((Attack - Defense) / 2 + bonus damage) * (1 + (Power - Resistance) / 400)
 * damage = ((300 - 100) / 2 + 35) * (1 + (150 - 50) / 400)
 * damage = ( / 2 + 35) * (1 + / 400)
 * damage = ( + 35) * (1 + )
 * damage = *
 * damage = 168

Therefore, a Backstab cast under these circumstances would deal 168 points of damage. However, damage calculations are ignored should Backstab automatically down the target.

Availability
Backstab is available to the Pierrot class series, an Item-dependent class accessed by equipping a Mysterious Card to the appropriate Adept. Since the Mysterious Card is only found in The Lost Age, Backstab is limited to the eight playable Adepts of that game. Backstab is learned at Level 29, but is not initially available. To obtain Backstab, the Adept in question must be in the Punchinello or Acrobat stages of the class. To reach the Punchinello stage, the Adept must have 6 Djinn, divided equally between the three elements other than the Adept's natural alignment. The Acrobat stage requires 9 Djinn, divided in a similar manner.

Analysis
General: Backstab is equivalent in power to Psynergies like Ragnarok, but will do slightly lower damage in practice due to the Pierrot class's lower Attack. In addition, it is over double the cost of Psynergies of equivalent power. However, Backstab does have the ability to instantly fell a target, which helps to make up the difference. Since most bosses are immune to such effects, however, Backstab's usefulness would be limited to random encounters.