I very much doubt that the leather on the meermin shoe was originally so dark. Usually it starts with a very light color and darkens with use of darker tone shoe polish.
Even in any tanneries, nobody will dye the skins in a dark brown/ black color before making the final product lighter color again. The color progression always follows light to dark. It doesn't make economic or productive sense to work with a darker color, stripping it and starting again.
That's normally how it works but what would have caused the dark spot then? Pretty sure the Saphir light brown cream polish doesn't darken leather like that.
