I'm In Love With My Bestfriend's Billionaire Fiance! - Chapter 11: Casey: Beyond A Love Triangle

Fate is a funny thing.

[A soul forsaken by the Gods and a body on the verge of death - The Darklord of the Endless Abyss has noticed your existence and is offering you a contract. Will you accept?]As he lay on unfamiliar land, his body covered in wounds and blood, Levi heard the voice of providence that he had craved for years.In a magnificent and mutated future, the advancement of technology and space exploration has opened new paths unknown to humanity. Being the curious creatures they are, and with hopes of saving the dying Earth suffering from resource depletion, humans began to explore these unknown lands.It was there that they discovered the treasures of the otherworld - artifacts and magical items that defied all scientific knowledge. But along with these treasures, humans also encountered dangerous and vicious monsters capable of tearing them apart with a flick of their fingers.However, humans were persistent. The treasures of the otherworld were too enticing to ignore. They struggled against the odds and found a way to fight these monsters by making contracts with the gods.The gods of the unknown lands bestowed extraordinary powers upon humans in exchange for the promise of extinguishing all the monsters. But not everyone was so fortunate, like Levi, who failed to pique the interest of any gods, and became one of the Forsaken.The Gods had forsaken him, so Levi decided to forsake the world - he made a contract with the Demon King himself!

The first great emperor in the world was betrayed by his confidante and perished. Millions of years later, the great emperor’s soul returned and was reborn as Ye Yan, the son-in-law who was kicked out by the Chu family with a letter of divorce, restarting the supreme journey. Open the gate of immortality, kill the Jiuzhongtian, and cast an invincible name again!

- Description from novelbuddy

Set on a giant, almost finished bridge between Sadogashima and Niigata. Abandoned by the government, the bridge, and the giant man-made floating island at the center, has become a city of criminals and societal drop-outs.

Set in the same world as Durarara, but 15-20 years later. There is almost no overlap between Etsusa Bridge and the other novels.