Shiny is correct!
The answer is the Tactician Overdrive mode.
Malady makes for fine transaction - Inflicting a neg. status on an enemy fills the bar up.
Recipient wanting for puissant action - You want to fill the bar up to unleash an Overdrive, obviously.
Victors' man of perspicacity a namesake - This is just trying to show the word 'Tactician'.
Blue, fanged, the greatest potential of all - Kimahri is the character who can learn the Overdrive mode the soonest, he only has to inflict statuses 60 times, the others all have to do around 75-100 (depending on the character.).
It wasn't exactly a well written riddle or anything, but hey.
Shiny's up.