This world rotates alongside what you believe, you define it as a cruel place where every kids kill others to survive until they grow up and die, or you can believe it as an amusement park where all kids can enjoy themselves and stay naive!
Faith needs motive, which in this story, is the pursuit of immortality, the hope of doing something from being forgotten, the courage of entering eternity without worrying about the actual harm & threat of death.
The reality is, believing can't prevent the virus to take away life, but it was so precious that survivors can use such belief to summon more of their kind, which is such an romantic reflection to reality.
Faith needs motive, which in this story, is the pursuit of immortality, the hope of doing something from being forgotten, the courage of entering eternity without worrying about the actual harm & threat of death.
The reality is, believing can't prevent the virus to take away life, but it was so precious that survivors can use such belief to summon more of their kind, which is such an romantic reflection to reality.