GANTZ is a Japanese exciting comic book.
The world view of it is a little complicated. Let me explain about the story.
It goes without saying that if you die you can't return back to your life.
But in the world you are called back to a room with the figure just prior to death if GANTZ choose you after death.
What is GANTZ? It is a black ball with radius about 50 cm.(You see the image)
It gathers the dead and make them battle aliens.
It is unclear who created GANTZ and why it was done.
But you can know the details and the situation change as the story goes.
Uh...it is difficult to introduce it in detail.
Anyway, I love the exciting battles and the stories of each character.
So if you are looking for exciting comic books, I recommend GANTZ highly!