[Anime Crossover] Are Secret Identities and Book Fragments Drawn to Each Other?

(Trying to save a really long story xx)

To make it easier for fans of obscure anime heartthrobs to find this, I'll add their secret identity names after the main character's name.

Blurb:

Hayakawa Ryota is given a "mission" by the will of the world.

[When the apocalypse comes, you wake up in a vast wasteland... and there's no one else to be found.]

For the sake of the world's past, present, and future, Hayakawa Ryota makes agreements with the "pillars" of other worlds. He uses their bodies, still imbued with memories and emotions, to travel to the [past] and collect fragments of a book.

A red-haired wanderer walks the streets of an era not his own;

The lord of the Night Parade of One Hundred Demons roams the present day;

A wandering god slays monsters and demons with his blade;

A mushishi quietly lights incense to repel insects...

[For the world, and for myself.]

I mainly just want to write about obscure anime heartthrobs! When he's using a [secret identity], he'll go by that identity's name, so I'll update the names in parentheses after the main character's name from time to time (I'll add them as I write about each one xx).

Strictly speaking, they're not secret identities (?). I just want to write about these heartthrobs!

Warnings:

1. Lots of out-of-character behavior and many original headcanons.

2. A crossover between worlds, with lots of alternate-world arcs.

3. The plot and logic may not make sense. I'm really bad at this.

Theme: Life holds countless possibilities.