Imperio is a boss in Final Fantasy Dimensions. He is encountered inside Castle Avalon, after Cocytus and Shango were defeated . Defeating him immediately triggers another fight with his own reflection, Gehenna.
Imperio usually strikes more than once per turn. Critical, Takedown, Right Arm and Swing are very typical moves that deal physical damage. He also fonds of casting Shell and Protect. The general sometimes counter attacks with Mind Blast. His most powerful one-shot moves are Flare and Judgment. The former deals more damage while the latter will inflict Attack Down, Defend Down and Magic Defend Down. Finally, he likes to combine Shellshock with Divine Shot to boost the damage further.
Since Imperio's element is Light, Light-based weapons and attacks like Holy, Ivory Slash and Final Heaven are useless. However, he's weak against Dark so Darkswords and Ebony Slash can be exploited. Other attacks such as Flare, Meteor, Phantom Rush and Midareyuki will hurt him badly.
Imperio often buffs himself up along with using abilities that can debuff the party. His rapid attacks, combined with debuffs, can deal major damage. There should be at least one character to deal with his debuffs and dispel him when necessary while having another character heal the party constantly. The characters' HP should be kept above average as defeating Imperio is only halfway through the fight.