>>56778265No, in fact its origin is western, both in Greek stories and in the name appearing for the first time in the Cilia comic from Vampirella Magazine, the Japanese only connected two points that at the time were not so obvious.
Now with all the information it is easier to see what the original source of the myth was, and its version is more aesthetic for merchandising.
Octopus people have existed in multiple mythological accounts, they just didn't have a name as a species until 1972.