u/ge-tout

So in the first world , there was no Devil fruits or any concept of it , there were actual beings , a real sun god , forest God , earth God , etc. and there was one more being, a real devil . So my theory is that the devil has the same and even more powerful abilities thn nerona imu , the devil and the sun God were always in a fight and the sun God always defeated him, so one time the devil instead of domi reversing the adults he decided to domi reversi the kids as the sun God will hesitate to hurt the kids so the forest God got an idea that what if he extracted the haki of the Devil and put it in fruits ,he was successful in doing so and gave the fruits a different look so that people could defferentiate between the normal and cursed ones, the Devil was again defeated by Sun god and his friends and once and for all the devil's remaining haki was also released inside a fruit which was , you're right , the akuma no mi .

after the war in the first world , after the serpent of hellflame (the redline) divided the world in half, the forest God made devil fruits and the sun God started another war , the D clan or half moon people and the full moon people fought for their rights and wanted to be recognised. the 20 kings betrayed the sun God and became Gods themselves, the sea God ( DAVY D. JHONS) cursed the Devil fruit prohibiting them from entering the sea, the sea God and the sun God will never meet again. (drop your thoughts)