There is no life without a game. Book 6. Kamia Yu.

A few thousand years before Sora and Siro fell into the dysbort and the legend began, known to everyone, and another legend had a place - all forgotten. This is a story about the Great War, which lasted from time immemorial, about how the scorched earth was fertilized by blood, and from the crimson heavens, without stopping, the ashes fell. About how weak and helpless were people who did not even hope for happiness and tried to just survive, so that at least their descendants would someday see something other than this war. And about a man and a girl who wanted to put an end to her and challenged the whole world, deciding to consider what is happening just a game.

is this story true or not? Is it so important?