Beyond Mortal by Cullen Bunn

Empire City...a metropolis of bright lights and gleaming steel...thrives under the protection of an Alliance of amazing heroes who protect the innocent and battle for truth and justice. Unknown to this league of super-beings, the city...indeed the world...has a cancer growing at its heart. A pantheon of ancient, cosmic gods is starting to awaken. These timeless forces of supernature once claimed dominion over a primordial Earth...and they have returned to reclaim what is theirs. Super-powered heroes - and villains - find themselves in a hopeless struggle against unimaginable horror to save the planet.

The unstoppable force of the Leviathan will collide with the immovable object of the world's most powerful superheroes in an unflinching tale of ultimate horror and ultimate sacrifice.

Superheroes versus elder gods.