The story was role reversed (half demon kagome,born a human inuyasha) but set in the feudal era. Kagome is I believe a runaway wolf (half) demon of some powerful family with some pack issues (I think one of her past traumas is a rape by possibly kouga), and Inuyasha is something like the village chief's son protecting the jewel. He really does not like her at first, and for some reason they go to a journey through the demon kingdom's where we find out more about Kagome's past, figure out why inuyasha is such a strong warrior, visit sesshomaru's kingdom (he knew kagome and her sister kikyou in their youth because of ther mom, it was neat how they were almost like extended "family").

There was a plot point about how Inuyasha was a particularly good fighter/had some kind of special power because he had been given a drop of demon blood somewhere in the middle by his human father (possibly thanks to seshomarus blood).

This is all I recall atm, I think it had many chapters but don't recall it being completed... I think it was listed as not romance, with potential inukag endgame however it was so slow I'm not sure in regards to the romance I don't think it got there (which is why I'm searching for it here too, besides the not knowing where else to go). Shippou is a cutie as usual and joins the gang and bonds with kagome. I think it starts with inuyasha and kagome meeting in the forest but she was in human form and at some later point in the start chapters he realizes she is a half demon but I'm not sure, this is a meeting scenario in many fics.

I tried sorting through ff.net and AO3 but I'm sad not to find much since I probably read it a couple of years ago. If this tickles your memory or you have some cool recs with a demon or half demon kagome to soothe my soul lmk.