I think Mofu-san has stated in the past that he would like to include another Dryad like futa girl who might be an enemy in the future.
It was a couple months ago when someone (don't remember user name) asked if there'd be another dryad girl or girl with tentacles, similar to Tilo in the comments page and Mofu-san said he would like to add another or a girl with tentacles.
This doesn't mean he would definitely include one (as I stated above) but that he is open/considering it, so I'm assuming Mofu hasn't done a design or listed a potential character in the dev log. They may, or may not include one in the future.