Omniscient

Omniscient is a boss in Final Fantasy V. He is one of the bosses guarding a spell in the Two Towers. Omniscient is guarding the Flare spell.

Strategy
Don't attack Omniscient. If you do, he'll cast Return, reseting the battle. Only do this if you're near death and can't heal anymore. However, that shouldn't be the case since Omniscient is very easy.

The best method is to cast Berserk on him. Now he'll no longer be able to attack or cast Return, so your party should be safe. Another method is to cast Carbuncle, so you reflect all his attacks back at him. When he dies, he casts Flare, but provided you still have reflect on your characters, or he's berserked, there should be no problems.