Uniqueness of God

In 4071 AD, the Alka Federation developed the first type of space jump gate. They finally got rid of the constraints of a world the size of only three planets and traveled to other worlds. In other universes, they saw immortal elves, new humans with advanced technology, and powerful and prosperous magic empires. But what is incredible is that their civilizations all share the same beliefs. "What? Do you also believe in time-travelers?"