Submerged City

Book One of the series "Elemental Cites" by Alex Sanchez. And no it does not bear reference to games and others, just the series title that came in to mind.

"After every end is a new beginning. The planet Earth after surving a catastrophic event begannto cater civilizations once more. But those civilizations don't just welcome humans.

Upon the renew of Earth gods and goddesses decided to dwell on the planet to bring peace and prevent further chaos, or just that they have nothing else better to do. Upon this new age, five capitals stand and are governed by three deities each."

For decades there was harmony, but as all stories are told, peace doesn't last long.