@RainGnyu Is that the one that is based on the photon blast gauge? If so, it does exactly what it says it does. As your photon blast gauge (which is the outline around the photon blast icon) goes up, the damage done by the weapon is increased, up to a maximum of 7% at level 3 at maximum photon blast gauge.
When the Photon Blast is used, an effect is added until the weapon is switched away from. But will be restored when switched back to.
Helix: Increase Power by 6%.
Ajax: Increase Active PP Recovery by 60%.
Ketos: Increase Natural PP Recovery by 40%.
Julius: Decrease damage taken by 15%.
Ilios: Reduce PP consumption by 20%.
(These are the JP names for the Photon Blasts.) The same effect cannot be stacked twice, but you can have every, one, of each, effect listed above in the same quest instance. An emblem will appear around the character based on what effect is triggered.