Kryptonian God Among Supernaturals - Book I

When Matthew comes to himself, he finds himself in his past self.
As he contemplates the advantages of traveling back in time and how rich he'll become by copying future novels, songs, and business ventures, he realizes from the conversations of those around him that this world isn't his old one, and that instead of going back in time, he's transmigrated to another.
A world where people have the chance to gain superpowers and devil fruits when they become adults.
Matthew manages to obtain the Logia-type Flame Flame Fruit from the Holly Land, where people gain their superpowers.
However, after obtaining the Devil Fruit while he was observing others entering and exiting the Sacred Realm, he encountered a strange sight.
Someone got Kryptonian Bloodline!
"Why does everyone treat the Kryptonian Bloodline like a useless power? Oh, in this world, sunlight doesn't reach Earth. So, doesn't anyone know how the Kryptonian body is strengthened?"
At that moment, Matthew makes a decision that will change the fate of the world he finds himself in.
"Hey, can you exchange your Kryptonian Bloodline for my Flame Flame Fruit?"
No one could understand why Mathew did that, but Matthew had a completely different thought.
"So what if the sun's rays don't reach this world? I'm the only one who knows how to strengthen the Kryptonian body. As long as I know what I need, it won't be too hard to find. And then humanity will meet SUPERMAN."
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