I don't know as I haven't read it. It could be anyone really, perhaps an ordinary person thrown into extraordinary circumstances that make them think their time is up.
I haven't read this novel specifically, but from the title, it might be about a character who thought their life was about to end. Maybe they were facing a life - threatening situation, like an illness or being in a dangerous place.
Since I haven't delved into 'I thought my time is up novel', it's hard to say for sure. But perhaps it revolves around the idea of time running out and how the characters deal with that sense of impending end, maybe related to lost opportunities or unfulfilled dreams.
To be honest, without having read the 'I thought my time is up novel', it's difficult to give you accurate reviews. However, you might find some in - depth analysis and reviews by looking up on literature - focused forums where people discuss different novels in detail.
Well, some libraries have digital collections of manga. You could check your local library's website. Also, there are dedicated manga apps like Comixology or Shonen Jump that might carry it.