Makoto Shiratori
About
The main character, who is plagued by insomnia by dreams of a city that does not exist. He is in love with Ai Kurosawa, but had not confessed to her
After interrupting his friend's confession to Ai to confess himself, Ai regains her memories and begs to be taken to Shinjuku before she is decapitated and dismembered
It is later revealed that (around chapter 40)
an older version of himself (in Earth A) is the creator of the world (Earth B) that he lives in, intended to be a perfect world where Ai is alive and he confessed.