Definitely Tales from the House of the Moon by Resmiranda (rated MA)
Hands down, one of the most angsty, heart-tugging and well written stories I have ever read and THE story that converted me from an Inu/kag shipper to a Sess/kag shipper. I was actually running out of Inu/Kag stories to read and saw that HotM has top reviews on ff.net, decided to go for it - it was the first sess/kag fic I've read. Best decision of my life, and have since been reading stuff on Dokuga for the past 3 years now
Even many stories after, if you're looking for a good emotional story, check out her work, you won't regret it, but you might need a huge teddy bear to hold after.
Another top top top favourite of mine that kept me in the fandom are RosieB's
- The Once and Future Taiyoukai (M) and
- Beside You In Time (M) (incomplete)
These two ladies have some major talent, if their stories were real people, I would have asked them to marry me.