Is Katrina going to actually end up anything like in the background image? Also, can there be a futa option for her, with her having an inconsitent form?
My guess is that she might be a bakeneko, given the closest folkloric correspondence I know of, even down to how the bakeneko concept may have originated as a variant of the shikigami ("familiar" in Western terms, yes, familiars came from Japanese folklore, and so did ogres even [not Medieval European folklore, ogre tales came later to Europe, like tales of familiars during the actual Middle Ages]) concept like the inugami is a relatively well-known example of. I don't think Katrina really HAS to be a familiar, but the idea makes sense to me.
The concept of orcs was ultimately derived from Persian mythology though, and long before the earliest known ogre ("oni" in Japanese) tales, so the Japanese must have been influenced by merchants from the Middle East. The reason orcs entered modern fantasy tropes is because of Tolkien influence, but orcs ("div" in Farsi, something like "daewa" in Avestan) did not originate there. Tolkien was evidently influenced by the Shahnameh, a Medieval Persian retelling of Zoroastrian myths, and even the term "Asmodeus" originally derived from a Greek mangling of the Avestan term for "white orc".