Personalities and characteristics... (Skippable)

Well, I know it's late to do it now, but let's do it anyway. It can reduce some confusion, at least. I am introducing this now because all the characters were not introduced during the early chapters and it would have also ruined the suspense.

So, I hope you will forgive this poor author.

Character introduction: 

Rio Flash: 

Characteristics: Dark black pupils and hair.

Expressionless and ordinary face. 

An individual reborn as an extra in the novel he read in his previous life.

His friend gave him that book, and he read it casually, just like he has been doing always. But when he woke up the next day, he found himself in the body of 'Rio Flash'. 

He has a good memory, but he wasn't a superhuman in his previous life after all, so he doesn't remember the novel he read from word to word.