World of Darkness: Reloaded
The ancient gods did not die fully, they just became less powerful. The spread of Monotheism has taken away Faith, the easiest power source. Short on power, gods die. The ultimate goal of nearly every god is the re-ascension of their pantheon. This requires followers and a prophesied quest leading to a cataclysmic, resurgence event (varies by pantheon).
In recent years, word spreads of Indra, Odin, Zeus, Ra and others. Many soothsayers claim a new age of the gods is beginning. But, when one pantheon ascends, all other gods will be forced to assimilate or resist and die.