Behemoth is an enemy in Final Fantasy IV: The After Years. They are powerful foes, counterattacking with extremely powerful physical attacks and countering spells with Maelstrom on the party, reducing them to single digit HP.
It is advised to keep any healers on standby to heal while having all physical attackers attack, though it may be necessary to keep another person on standby to heal/revive party members that need it.
In Edge's Tale, the Behemoths are the tail enemies of the tale, dropping Purple Tails. The easiest way to defeat them is to use Ninjutsu on them to provoke a Maelstrom, then use the Band Advent of Phoenix. Advent of Phoenix does more damage the lower the party's HP, and with all members at Level 40 and at single-digit health, will do over 9,000 damage, leaving the Behemoth weak enough to kill with a normal attack. The player can then use a Potion on the members to give them enough HP to survive an ambush attack from normal enemies, and against the next Behemoth can use Advent of Phoenix right away. The Behemoth may counter Advent of Phoenix with a normal attack, likely killing whoever it hits, but they can quickly be revived.
Behemoth is a beast mentioned in Job 40:15–24. In addition to mythological creatures, it is likened to elephants, hippos, rhinos, and bison. Metaphorically, the term behemoth denotes "an extremely large or powerful entity."