Lunarians are by far the most powerful race we have seen so far. In his battle with king, zoro implied that even with ACoC and ACoA, it wouldn't be very effective to cut king when his flames are up. The fact that king's flames can allow him to resist such powerful attacks shows how powerful the lunarian defense actually is. The only way to kill someone like King is with advanced haki mastery or advanced devil fruit mastery.
I believe the latter could have been the way the lunarians were defeated in the first place. Both in real life and in fiction, human ingenuity has always been mankind's secret weapon, the one that gives humans supremacy over other races and animals. I believe this was the case in one piece. And that in order to overthrow the lunarians, mankind invented devil fruits, which could give men the ability to kill gods.
DFs are quite commonplace in the series, but imagine hundreds of years ago in the battle between lunarians and mankind. Men invented the devil fruits and hence had all of them. All the logias, all the mythical zoans, and all of the overpowered paramecias. The lunarians had nothing but their own natural strength, and hence they were destroyed.
I believe the latter could have been the way the lunarians were defeated in the first place. Both in real life and in fiction, human ingenuity has always been mankind's secret weapon, the one that gives humans supremacy over other races and animals. I believe this was the case in one piece. And that in order to overthrow the lunarians, mankind invented devil fruits, which could give men the ability to kill gods.
DFs are quite commonplace in the series, but imagine hundreds of years ago in the battle between lunarians and mankind. Men invented the devil fruits and hence had all of them. All the logias, all the mythical zoans, and all of the overpowered paramecias. The lunarians had nothing but their own natural strength, and hence they were destroyed.