Well, Marduk is a Lord of Order. He is a child of Tiamat, the Dragon of Chaos, and is responsible for overcoming Her in the great battle for the cosmos.
He has been described as stern, and not to be evoked for trivial matters. Those who like to claim that all spirits are really just masks of certain popular spirits equate him with Jupiter, Lucifer, Yahweh, Baal and Azazel, among others.
This gives a brief description of what he is like: