She is his biological mother (or the dialog is contradictory)

Biological moms most definitely aren't the only ones who can breastfeed. There is a distinction between wet and dry nurse exactly because of that.

@IDontWishToBe ok, good to know. still not believable that his stepmom was breastfeeding him, so most likely it's a dialog error.

@Zarutaku I´m pretty sure I read online that she is indeed his real Mother in the Original but somehow made into his Step-Mother in the Hanime due to... idk why exactly :D. Takes out the spice a little bit xD. But yeah, originally she was his bioligical Mother.

@MarkB1337 interesting, now i'm just surprised that the source material isn't listed here, seems the database isn't as complete as i thought.

She is his one and only biological Mother in the source material, so he's half succubus himself lmao.

The author wrote about it on his blog, he was pissed because the production company wanted to change it to Mother in Law because it could be marketed to more people. So you'll see both versions depending on which sub you choose.

They did the same thing with his other work where the FMC is the protagonists older sister. They changed it to step sister for the anime which he made another rant about lol.