Leviathan (Final Fantasy V boss)

Leviathan is a boss that guards Istory Falls in Final Fantasy V. He protects the ancient tablet that lies there, but the player's party does not need to fight him. Instead, the party can return later to fight him.

Strategy
Your main concern here will be Tidal Wave, which can be absorbed if you have Coral Rings, besides this you only have to take care of his physical attacks and damage him, preferably with Lightning-based attacks.