Out there somewhere in the unlimited expansive universe God stood there bored. He had made many universes resembling fiction places but no one to use it on. Ever since he existed, he has always been a bit of a watcher. He doesn't like playing the games, he liked watching others play the game. He loved seeing people react to certain situations. The most people react is when they are faced with something dramatic. God has made a lot of experiments. Some with happy endings, and many not so great. But all of these got a certain reaction from everyone.
So he thought, what if he put his favorite creatures, humans, in one of these worlds. They could pick a world and go there. Depending on their karma, they would get a demonic version of that world. Or maybe he could make a system like one of these novels he recently read. How would a relatively normal boy in the twenty first century react to the breath taking powers that the system holds.
That's it. He decides to put his greatest effort in making the greatest system ever. He shall combine aspects of what makes other systems great and put them into one. He shall call this system...'No, it's better to let the host choose it's name' he thinks. And with that the greatest system is born .