Froth, Froth Sphere, and Froth Spiral are offensive, ranged Psynergies. The total damage inflicted is determined by comparing the caster's Mercury Power to the target's Mercury Resistance and using this number to modify the base power of the particular Psynergy in use.
Visually, each stage of the Froth series features a group of bubbles forming near the caster and striking the targets. Upon impact, the bubbles transform into a blue colored spiral figure. The number of bubbles and spirals increases with each successive stage.
Elemental Power attacks such as Froth, Froth Sphere, and Froth Spiral use a set base power as the base damage to be modified. For example, the base power of Froth Spiral is 150. Thus, an unmodified Froth Spiral would do around 150 points of damage.
Attacks from each stage of the Froth series take this base damage value and uses it in the following equation:
- final damage = (base damage) * (1 + (User's Mercury Power - Enemy's Mercury Resistance) / 200)
To word this in prose, Froth, Froth Sphere, and Froth Spiral take the base damage of the particular attack, and then modify it by how much higher or lower the user's Mercury Power is than the target's Mercury Resistance. The difference between the user's Mercury Power and the user's Mercury Resistance is then divided by 200, 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 a Mercury Power of 150 casts Froth Spiral on a monster with a Mercury Resistance of 50:
- damage = (base damage) * (1 + (Power - Resistance) / 200)
- damage = (150) * (1 + (150 - 50) / 200)
- damage = (150) * (1 + 100 / 200)
- damage = (150) * (1 + 0.5)
- damage = 150 * 1.50
- damage = 225
Therefore, a Froth Spiral cast under these circumstances would deal approximately 225 points of damage to the targeted enemy. Since Froth Spiral is a ranged Psynergy, adjacent targets take a percentage of the total damage, with the percentage decreasing as distance from the main target increases.
The Froth series is available to the Mercury version of the Seer class series, and the Medium class series. Thus, it is available to Mercury, Venus, and Jupiter Adepts. Mercury Adepts generally require large amounts of Venus Djinn to access the series. Non-Mercury Adepts require varying numbers of Mercury Djinn. Both classes learn Froth at Level 2, Froth Sphere at level 14, and Froth Spiral at Level 40.
The Froth series is weaker than many endgame Mercury series, such as the Prism, Ice, and Cool series. However, it is usually available much earlier, when its power is useful. Despite its lower power, it is the strongest series available to both the Seer and the Medium, and is important for inflicting damage should either of those classes be in use. It should be noted that the series is the strongest Power-based Mercury series available to Venus Adepts, barring the use of Item-dependent classes in The Lost Age.