The Tanakh is probably too big to post, but it paints a very detailed description to the nature of (a)Leviathan.
More random info.
"In Psalm 74 God is said to "break the heads of Leviathan in pieces" before giving his flesh to the people of the wilderness; in Psalm 104 God is praised for having made all things, including Leviathan; and in Isaiah 27:1 he is called the "wriggling serpent" who will be killed at the end of time."
"When the Jewish midrash (explanations of the Tanakh) were being composed, it was held that God originally produced a male and a female leviathan, but lest in multiplying the species should destroy the world, he slew the female, reserving her flesh for the banquet that will be given to the righteous on the advent of the Messiah (B. B. 74b)."
sad Leviathan, no wonder he's pissed:
"The enormous size of the Leviathan is described by Johanan bar Nappaha, from whom proceeded nearly all the aggadot concerning this monster: "Once we went in a ship and saw a fish which put his head out of the water. He had horns upon which was written: 'I am one of the meanest creatures that inhabit the sea. I am three hundred miles in length, and enter this day into the jaws of the Leviathan'" (B. B. l.c.)."
It makes me imagine a rise of Inarius and possibly an apocalypse rising for all of the Diablo universe with a Behemoth and Ziz like characters. http://en.wikipedia.org/wiki/File:Lev-Beh-Ziz.jpg
Also Belial is: The term belial (בליעל bĕli-yaal) is a Hebrew adjective meaning "worthless"