Behemoth King is a powerful enemy who uses both magical and physical attacks. When defeated, it unleashes Meteor as a final attack. The final attack can be avoided if Behemoth King is killed as a result of a counterattack, a taming weapon (no longer works once the capture limit has been reached), or Yojimbo's Zanmato.
NulShock protects against Thundara and Thundaga, though these are not Behemoth King's most devastating attacks. Its most dangerous move is Meteor, but Protect and the defend command both halve the damage. Combining them mitigates Meteor's damage to 1/4. The player can also use Stamina Tablet/Tonic or Auto-Life. An easy way to survive is to have one party member escape before Behemoth King uses Meteor, so even if the party is wiped out the player does not get a Game Over.
Since Meteor is not triggered by the Behemoth King being killed by a counterattack, the player can give a character with Provoke a Counterattack/Evade & Counter weapon, then provoke the Behemoth when its HP is low and defend until it dies from the counterattacks.
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."