Leviathan

The Earth is cursed, humans scrape meager livings from the soil, and legendary beasts roam the wilderness. When a fearsome leviathan threatens his homelands, Noah must find a way to defeat the monster. Desperate to discover its weakness, he journeys to seek the aid of the half-angel giants called the Nephilim. Meanwhile, the angelic Watchers known as the Grigori have seized the great city of Enoch, and their powerful leader has become obsessed with Noah's bride-to-be. Friendships and faith are tested, and Noah is thrust into the middle of an impossible revolution against the fallen Grigori. His Nephilim comrades must choose whether to fight on the side of humanity or the angels, and their decision may mean the difference between the earth's salvation and its annihilation.