My theory is that Minks, Fishmen, Oni and Lunarians are Earth’s original inhabitants.
But for some reason, sometimes monkey Minks were born without fur.
As Wanda mentions in the image above, Minks are proud of their fur. I speculate that fur was the catalyst that drove ancient Minks to develop the Electro powers.
Now, you might think, if fur is all that’s necessary then why can’t normal animals use it?
Compared to other animals, Minks are a sapient species with the intellectual capabilities of humans.
Them making use of their intelligence to enhance their bodies’ natural properties would not be far fetched. Likewise, Fishmen developed Fishmen karate that utilises water.
Over time, Electro became an important tradition in Mink civilisation and fur became a defining element of Mink identity.
It is a logical assumption that any (monkey) Mink without fur would face repercussions and would have been excluded from many aspects of society.
Like Wanda mentions in the panel, the lack of fur makes you a “lesser Mink”. In the distant past, those hairless monkey Minks might have been treated as second class citizens and would face discrimination, maybe they were even expelled from community events or forced to live in a seperate place/village.
One day, a hairless monkey Mink with exceptional willpower didn’t want to put up with this any longer.
This individual who would become the founder of the Monkey family, was Nika.
Nika opposed the discrimination of the hairless Minks, he would bring joy to his people and inspire them to fight for their freedom.
To make up for their lack in power from their missing fur, the hairless monkey Minks would develop technology and later the devil fruits. Over time, they evolved into their own species (Humans). They formed their own civilisation and their own culture, seperate from the Minks.
But because they became reliant on their technology, humans grew weaker than the other evolved species on earth.
Then, at some point in history they used their technology to travel to the moon and make a new home for themselves.
The return to planet Earth
We already know from Enel’s cover story that the humans from the moon had to leave it for lack of resources. It was a sad departure as they had to leave their humanoid robots behind.
At that time, humans had already formed highly technologically advanced civilisations.
Maybe the evolved non-human species on earth didn’t like their “new”/old neighbors. Due to their physical advantages and elemental powers they still saw themselves as superior races and persecuted the humans with the goal to wipe them out.
As a response, humans used their advanced technology to create the devil fruits.
(I’m not exactly sure whether to place the creation if the devil fruits before the journey to the moon or after the return to earth. The assumed presence of the devil fruit tree in Mary Geoise makes me favor the latter scenario).
The combination of technology and devil fruits gave humans an advantage. They were now able to stand their ground, create more offspring, raise their numbers and eventually out-breed the others (maybe loosely inspired by the alleged relationship between homo sapiens and Neanderthal).
The humans, now immensely powerful, came to be arrogant and went on to persecute the other species with the result being the Lunarians’ and Oni’s near extinction while the other species were forced into hiding/secluding themselves. The minks chose the safest way, living on a gigantic animal that can’t be tracked down with any human navigation apparatuses. Unlike islands, Zunesha lacks a magnetic field.
The age of human supremacy
Over time, humans diverged into two factions: one wanted to reconnect with the other species and promoted equality, the other wanted humans above all.