Moloch is one of the first Gods worsjipped by mortals, and was the dominant deity for centuries. He was the god of fire and the forge, and he insisted that a steady stream of babies be sacrificed to the fire. (side note - this is historically "true"). However, his demands for such a cruel sacrifice eventually led mortals to turn to other Gods, and Moloch slowly withered away to almost nothing.
Centuries later, Molochs dwindling essence was discovered by another god, Gondwyn the Eladrin God of Creativiy, who had become similarly orphaned. The two fused and became Gond, the God of Invention. This new God was discovered by a peculiar race of sand gnomes called the Al-Bhed, and under Gond's tutelage tjhey created all manner of wonders. But they always had to sacrifice their flesh to do so.
Then one day the Al-Bhed met a mortal named Erick, who convinced them there was another way. They turned their backs on Moloch, and he once again began the slow process of dying from neglect. As he lay dying, he swore revenge. He found the mortal Erick and appeared before him, and swore to use the last of his power to drag Erick back into the abyss with him!
Moloch attacks Erick with all his might, but due to his extremely weakened condition, the party was able to destroy him; making him the second God they have killed. Erick eats Moloch's heart and absorbs some of his essence.