The Era of Super Powers in a Parallel World

Traveling to a parallel world, the boy discovered that this world had super powers. But as he slowly learned about more things, he discovered that the world was not as simple as he imagined: What exactly is guarding the human frontier? What is the origin of superpowers? What secrets are hidden in ancient ruins? What is the "god" that cults believe in? Why do the rebels want to kill all those with innate superpowers? As he grew up again and again, the young man saw a world he didn't understand at all. "I always thought I had seen through the world, but in the end I found out that I had only seen the tip of the iceberg..."