Megistotherian is an enemy in Final Fantasy XIII, fought on the Archylte Steppe. It is seen fighting the Behemoth King and seen accompanied by Gorgonopsids. Megistotherian appears to be a larger version of the Silver Lobo.
In the battle with Behemoth King the player will always get a preemptive strike, and the two will keep fighting each other until one of them is defeated, at which point the one left turns on the player party. This is why the player should aim to kill the Behemoth King first (as it is stronger of the two) by quickly staggering and launching it, so it will not have time to recover its HP.
Megistotherian itself is not a difficult enemy. It is weak against Fire and takes half damage from magical attacks.
Megistotherian is also an extinct genus of creodonts.Megistotherian means "greatest beast" in Greek.