MTL - Age of Mysticism - Chapter 372 prototype

I was born into a prestigious martial family, yet I was nothing but a useless person with no talent whatsoever.At least, that was the case until I was trapped in a dream.[You cannot die here.][You can not lose your mind here.][Time does not move in this place.][You cannot leave until you reach the extreme.]Geniuses and fools—people say these are two unchangeable truths of the world.They claimed that I could never enter certain realms because I was a complete fool.But when a human body and soul are thrown into the extremes of time, they adapt.[Congratulations. You have reached the extreme.]Now, it is time to leave.

High-school student Koremitsu Akagi finds himself attending the funeral of Hikaru Mikado, who had died in an accident during Golden Week. He’s not sure why he’s there, as he only exchanged a few words with Hikaru at school. However, Hikaru doesn’t seem to be completely gone from the world, as he comes back as a ghost in order to fulfill a promise to Aoi Saotome, his fiancée. Since Koremitsu is the only one who can see him, he asks him to carry out his promise in his place.

Complying with his request, Koremitsu tries to fulfill Hikaru’s promises to the rest of his “girlfriends”, helping them overcome past misunderstandings and repair broken relationships.

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.