The name "Behemoth" derives from the archaic Jewish name for hippopotamus, from the Hebrew behema. The Behemoth is a monster described in Judeo-Christian lore, and is one of three primordial beasts said to symbolize the physical world. He was represented as the the largest and most powerful of all land-dwelling beasts, was herbivorous and dwelled in swamps. Behemoth is said to rule the solid earth and is often depicted as a gigantic creature of unknown origin (though it has been identified with many large animals, such as hippos, elephants or bulls).
The Behemoth, or Behemot, is the primal monster of the land, as the Leviathan is the primal monster of the sea, and the Ziz the primal monster of the sky. Originally considered a chaos beast, the Behemoth was either confronted by God at the beginning of time or near the end of time; in both confrontations, the Behemoth is considered a hulking brute of unimaginable strength that is defeated by God's omnipotent nature and either banished or reduced to a divine "pet." Legend says that at the end of the world, the Behemoth and Leviathan will kill each other, providing apocalyptic feasts for men.
Some depictions of the entity makes it an angel that join Lucifer's rebellion that fell and became a demon.
Devil Summoner: Raidou Kuzunoha vs. The Lone Marebito
Originally Shouten, one of Abe Seimei's minions, he was infected with Clarion's poisonous magnetite, which disfigured him and several of his allies. An uncontrollable hunger took over, leading him to eat his fellow demons and anything he could get his hands on, transforming him into Behemoth. Behemoth then spreads the magnetite that fuels Abe's plan and is then used as a sacrifice to summon Clarion.
DemiKids Light & Dark
"Beast of legend who's forgotten he's got the power to summon Doomsday."
"Nobody can stop this legendary beast who has the power to destroy worlds."
Known as Brute, he can perform the combo attack Dragon Cross with Doom Rox. To obtain Brute ones must first create Brutzom through Relic Fusion, then obtain his soul an fuse with it with the zombie.
Devil Children Messiah Riser
Behemoth appears as a boss within the ruins of the Imperium's former capital[Tyranog.
Devil Survivor 2
"A gigantic demon also known as Behemot. It was originally an animal mentioned in the Book of Job as a giant fish, but later generations referred to it as a demon that presides over darkness and tempts men to excessively eat and drink. It is an epicure and excessive eater itself, and its stomach is always swelled to its limits."