Ok...so I don't remember much just that Sesshomaru found Kagome's dead body in a hot spring and revived her...I remember some details like how sesshomaru wasn't the true heir to the west and that the moon was a 'tattoo' I think...I also remember that the true heir was sick and that when he died the mark of the heir went to Inuyasha instead...I'm pretty sure this is post naraku...so yeah...please help me find this fanfic...I've been searching this story for some time now...

Well, not all the details match (e.g. the hot spring part), but if this is an older fic (circa 2006) and if Sesshoumaru also had a bunch of concubines and a mate in this story, then it's probably my Crescent Moon. (Rated M!)

Thank you so much...I'm pretty sure this was the story...I think I might've mix it with another story cause for some reason I also thought that Sess didn't have a mate just an intended who Inuyasha soon mated...

Eh, it could be they weren't fully mated yet, it's been so many years since I wrote it that honestly even I am fuzzy on the details.
But I'm glad I could help!