Helm Splitter and Skull Splitter

Helm Splitter (かぶとわり, Helm Splitter) and Skull Splitter (どくろわり, Skull Splitter) are related Venus Psynergies featured throughout the Golden Sun series. The two Psynergies are unique in being functionally identical in nature, with only the names and class requirements changing.

Basic description
Helm Splitter and Skull Splitter are offensive, single-target Psynergies that are Attack-dependent, meaning characters with higher Attack ratings will deal more damage with these attacks. In addition, the caster's Venus Power and the target's Defense and Venus Resistance all factor into the damage dealt.

Visually, Skull Splitter features the caster lunging towards the target and striking a powerful blow. Yellow stars emerge from the point of impact. Helm Splitter is similar, featuring blue-colored spirits that emerge from the point of impact.

Damage Calculation
Elemental physical attacks such as Helm Splitter and Skull Splitter 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

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


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

To word this in prose, Helm Splitter and Skull Splitter take the base damage of the user's normal physical attack, add a set amount of bonus damage to that, and then this result is modified by how much higher or lower the user's Venus Power is than the target's Venus Resistance. The difference between the user's Venus Power and the target's Venus 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 Venus Power of 150 casts Ragnarok on a monster with a defense of 100 and a Venus Resistance of 50:
 * damage = ((Attack - Defense) / 2 + bonus damage) * (1 + (Power - Resistance) / 400)
 * damage = ((300 - 100) / 2 + 30) * (1 + (150 - 50) / 400)
 * damage = ( / 2 + 30) * (1 + / 400)
 * damage = ( + 30) * (1 + )
 * damage = *
 * damage = 162

Therefore, a Helm Splitter cast under these circumstances would deal 168 points of damage. It should be noted that the damage calculation will be bypassed should Helm Splitter's instant death side-effect activate.

Availability
Helm Splitter and Skull Splitter are unique to the Samurai class series, meaning only Venus and Mars Adepts can cast them, and only if they have a combination of Jupiter Djinn and Djinn of their symbiotic element set.

Both Helm Splitter and Skull Splitter are learned at level 33. However, only Helm Splitter is available at first: Many Psynergies are only available to the more advanced versions of a class, and Skull Splitter is no exception. What separates Helm Splitter and Skull Splitter from most Psynergies is that Skull Splitter replaces Helm Splitter. To access Skull Splitter, the appropriate Adept must be upgraded from the Samurai class to the Ronin class, which requires 4 Jupiter Djinn and 5 Venus or Mars Djinn.

It should be noted that both Skull Splitter and the Ronin class are not introduced until The Lost Age, so in the original Golden Sun, Isaac will only be able to use Helm Splitter.

Analysis
General: Helm Splitter and Skull Splitter's damage output is roughly the same as other elemental physical attack Psynergies like Heat Wave and Diamond Dust, but in practice appears to deal more damage due to the Samurai class series's higher Attack multipliers. Both Psynergies are roughly on-par with a mid-game Unleash (with the main difference of costing Psynergy Points instead of activating at random) and are more valuable the earlier they is acquired. Even in the middle and late stages of a game, both may be preferred over Unleashes due to its reliability. Though weaker in comparison to other late-game physical elemental attacks, their chance of instantly downing an enemy make them an excellent option in random encounters. However, attacks like Quick Strike will take precedence against bosses.

Vs. Djinn: Many, though not all, offensive Djinn use a damage multiplier instead of a fixed damage increase, in addition to the Power - Resistance multiplier. As a result, these Djinn have the potential to be much stronger than Helm Splitter and Skull Splitter, especially in the later stages of a game when the Adept in question has a higher Attack rating. However, unleashing Djinn in battle places them in Standby, resulting in two main disadvantages. First, Djinn must be Set to affect a character's class; unleashing a Djinni may result in lower statistics across the board, including Attack and Power, reducing the damage dealt by subsequent attacks. Second, a Djinni's effect cannot be used again until that Djinni is re-Set, which means either wasting a turn manually Setting the Djinni or using it to perform a Summon, after which the Djinn used must spend several turns Recovering before they automatically Set themselves. Either way, offensive Djinn cannot be repeatedly used as easily as Psynergy, making Helm Splitter and Skull Splitter more feasible for long-term combat. Alternatively, players may choose to combine both approaches: Unleash several offensive Djinn, perform a Summon, then use Helm Splitter and/or Skull Splitter to continue dealing damage while the Djinn are in Recovery.

By game
Golden Sun: Since Skull Splitter is not introduced until The Lost Age, players only have access to Helm Splitter in the original Golden Sun. It will usually be available sometime around Venus Lighthouse. The Samurai's higher Attack, combined with the instant death effect, make it excellent for taking down random encounters. However, it does compete with the Ninja class's Annihilation, which possesses the instant death effect, but also has a strong damage multiplier. However, if using the Samurai class for its buffing abilities, Helm Splitter will still be the most reliable offense.

Golden Sun: The Lost Age: Helm Splitter will typically be available around Jupiter Lighthouse, where it can be useful against the random encounters. However, by this time, the player will typically have stronger physical elemental attacks, which might be preferable. In addition, Annihilation will also be available, and be much stronger. Skull Splitter will be available to endgame parties, where its cheap cost makes it excellent for conserving PP. In most cases, however, it will be set aside for the reliable Quick Strike.

Golden Sun: Dark Dawn: Helm Splitter is available while exploring the Eastern Sea, making it a useful weapon against the various monsters encountered in the region. It does have more competition in the form of Annihilation, which is stronger, and Psynergy Slam/Psynergy Surge and Quick Strike, which lack the instant death effect, but are much stronger. As before, Helm and Skull Splitter are better used when attempting to conserve PP.