"There are many legends of great fish called leviathans that swim in the oceans of Ardania, but there are few living persons who can say they have actually seen such a fish."
From "The Overall Description of Everything" by Master Alfus Bumblegate
Advanced fighter. Spawns from Whirpool of the Leviathan.
Strong Scales: Resistance: +30 Melee, +15 Missile
Leviathans are much less of a threat than Sea Serpents. They're very low on hit points and cannot attack cities. Make use of the fact they don't have a ranged attack and shoot them from afar, even with basic military ships.
Three of them will sink your transport cog (each does around 5 damage), and they attack like piranhas - in swarms. Clean out unexplored ocean areas before sending land troops in.