Impact Psynergy series

The Impact Psynergy series is a Jupiter class Support Psynergy found in both Golden Sun and it's sequel, Golden Sun: The Lost Age. The series is available to the following class' and their stronger variants:
 * Apprentice
 * Wind Seer
 * Page
 * Hermit
 * Tamer

In perfect gameplay, this can become really useful, since there will be a moment when the unleashes of the weapons will become so powerful (normally multipying damage by 3) or even with psynergy based on attack stats (such as Call Dullahan) that boosting the attack stat will be a great way to augment your adepts' strength. It all depends on your strategy. It is also important to know that there is an identical psynergy accesible only to the Samurai class, the Demon Spear psynergy series.

Psynergy
Impact is used to "Boost [an] ally's Attack." Specifically it raises one Adept's Attack by 25%, and can be used again to increase it to 50% (the maximum any stat can be raised above its standard value). While the Hermit class series learns Impact at level 1, the rest need to wait until at least level 5, with the Tamer class series learning it the latest at level 6.

High Impact is used to "Boost [the] party's Attack" by 12.5%. It can be used repeatedly to further increase the party's attack, up to 50% higher than its starting value.