The world suddenly changes when the people awakened the power to control mana, aura, and other types of of energies to control and manipulate, these types of energies varies from making your body stronger and invincible to anything and to allowing you to create spells out of thin air to attack and also defend you.
Some of them can even heal and revive the dead throught having a connection with a god, or goddess and others that can summon beings from different races or ones that are mechanical throught imagination, while the humans are not the only one who recieved this blessing, animals also became stronger and become bigger some of the creature's from folklore and fairy tales also came to life of course not just them fables and legends also became real.
While all of that happened creatures from the past or events that happened in history came back.
But that was not all, the world also started to change and reverted back to the medieval ages but the ones that existed on the medieval peroid in the past dissappeared. So every structures and everything in modern period, transformed into something that only existed in the past.
Making it so that modern technology to be lost, only to be remembered in the mind of humans and only hoped to reverting everything back to modern technology, while also finding why the world changed.
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I think it also needs some parts added like 500 years later a tower appeared from a different dimension invaded earth, or something and the technology is already recovering to that in machine age, and some people have become very powerful that they have established their own kingdom, and some of them have already become very powerful enought to destroy a city in a second.
And later 1000 years later or more you can also probably add that the tower was conquered by someone or a group of people conquering it. And now 1000 years later someone reincarnated from that time and in this time the technology have reverted back to the modern age, but people don't remember the past because the world changes again after someone found the reason why everyone awakened and fantasies becoming real.
Making the earth before the world and everyone awakened reverted back to before, but everything is still the same only the environment changes, and people not remembering about the past or their ancestors. They only remember about present time and nothing else but the reincarnator who witnessed everything from 500 years ago will not let this oppurtunity slide. But what the reincarnator doesn't know that everything was changed by someone who have became a god, who defeated those who climed the towers and killed one of the conqueror of the tower who obtained a wish from the tower making that god invincible in the current present time.
The reason the god changed the technology of the past and reverted back to before and erasing the memories and history of the past was fear, fear of one empire that managed to create powerful artifacts that is made using technology of the machine age and magic and other types of energies.
You can also add that after the fight between the reincarnator and this god causing much destruction until the world was not transformed, but a separate continent made an appearance in the world and that was the one on the past that have its memories and history of the people erased, and so when it appeared all the people in all countries came to this continent that was much larger than the continent comebined. Althought modern technology is strong it cannot harm even the weakest monsters of this continent making the people, making the people name this continent as the dark continent and people ventured to this continent also found out that traces of their ancestors living there came leading to more people coming to this continent.
they discovered powerful artifacts and divine objects that only a few people can use as it was linked to their bloodline and structures and even cities, empires, villages have been leaved behind. Sometime later they also found the tower from the past but it was destroyed and nothing was left, and as they ventured and learned more about this continent and found out that the god the reincarnator found was not the only one who did this.
There are also those who have become too powerful in the past and some become gods, some of them left earth to find a new place to live and challenge, some of them opened portals or forcefully opening them with a slice of a sword to enter other worlds and the gods created their worlds to toy. And sometime later some people who have come from this world came back and when they learned what happened they were not happy as some of them were ones hailed as heroes of the world.
What do you think? Like you could make a novel of 4 parts with this idea.
So what do you think is my idea good? Or bad? Comment down and let me know.