Looking for a story I read a long time ago. I think it might have been on ff.net since that's where I first started reading fanfictions and it was that long ago.
It takes place in the past, after Naraku is dealt with. I remember Kagome was mated to Sesshomaru. I'm not positive but I think the story started out with them already being mated. Something happened between Kagome and Inuyasha and it's been possibly years since they had seen each other and probably the reason she's mated to Sesshomaru.
I think there was a war going on during the story between the West and somebody. Somehow Kouga kidnapped Kagome, a separate incident from the war, and kept her trapped in a cave, and was intending on forcing her to mate him. Either Inuyasha or Sesshomaru found her and saved her, and Kouga was killed. And it's possible that Rin is living with Kagome and Sesshomaru.

That's all I can remember for now. If I remember more I'll edit this post.
I hope this sounds familiar to someone.