Beautiful!!
It was great how you wove everything to fit the original Inuyasha story and just fluffed out the beginning and ending of the Inuyasha story with Sessh's POV. Yasha's past is so sad...from the summary I thought Sessh just killed him off once his dad died (I did hesitate whether to read this) but found their relationship was a bit more complicated than that. Though I hated Yasha dying and yes Sessh did end up killing him but in the end it really wasn't intentional as the poor Inu was quite conflicted himself. Yasha's death though a difficult one to write I'm sure, but I thought you handled it very well.
Was a bit of a shocker to find that Sessh's dad was a dog, I thought the mythology was pointing to the original ancestors of youkais not actually Taisho. So sad and explained quite a bit about Taisho's actions during his reign.
BTW Dai does mean big/great. There are a few ways to read Japanese Kanji (Chinese characters) and you're correct! :) It's the same character used in Daiyoukai (not Taiyoukai as many use as Tai is a different character altogether and actually a type of fish).
There was a maturity in your story that was refreshing and very appropriate. Loved how Kagome knew and accepted circumstances of Yasha's death without the drama. Your story is certainly intense and drama filled but without too much angst - it was just perfect.
The characters were also very IC and well depicted - Sessh's character developed beautifully. It was great how you nailed Rin's character too. She's a nice cute girl in the anime but in many FFs I find her to be more annoying as she seems spoilt/whiny or caps-lock screaming all the time. You do a wonderful job of altering the characters to your different stories - your Sesshomaru and Kagome portrayals area slightly different in each piece and wonderfully done. I've been going through like three of your works the past day - can you tell? I first found another lovely work of yours (Forever Entwined), and been moving through your other works (Scarlet Ties). Although both were incomplete and actually still very short (I rarely read incomplete or short stories as I prefer very long finished ones), they were a delightful read. While I enjoyed this work which was deeper and dealt with darker issues, the other two works show hints of fluff and romance (*yay*) which I'm looking forward to seeing how they'll develop.
It was a great idea starting and ending with the mythology. You had me in tears several times at the end!
Thanks so much and I'll be going through your other works (I was ecstatic to find you have quite a lot, and a few longer ones too!) so you'll probably see me popping up again as I plan to go through all of them if possible. Besides, I'll be checking out to see if you have any updates to your ongoing series. Stay well!