So...I'm guessing Sesshoumaru probably didn't mean to poison Inuyasha, otherwise he would've given him the antidote. He'll probably be pissed at Inuyasha for ignoring his pain once it got so bad, although from the hanyou's perspective, I completely understand why he did. He probably didn't realize it was truly serious, either. But hopefully a part of Sesshoumaru, even if it's just a secret part he thinks to himself but doesn't express out loud, feels guilt and remorse for almost accidentally killing his favorite pet. I still remember the fiasco with child Inuyasha's first new moon night, during a thunder storm no less, and Sesshoumaru's reaction when he realized the human boy was still his same little puppy, and how he had so easily and stupidly forsaken him. Sesshoumaru is definitely capable of feeling remorse for his heartless and/or careless actions when the moment truly calls for it. This situation is a little different, of course, because Inuyasha did not feel hated or cast out by his master. He thought it was only a stupid bite and was being harsh on himself for being too 'weak' because it was hurting him. Hopefully Sesshoumaru also feels some pride in Inuyasha for being able to endure it for so long. It was carelessness on his part because his own inner beast got riled up at Inuyasha's possessiveness. Clearly the reason Sesshoumaru is so against finding a mate, and is not being too bothered by his seasonal heats as an unmated male, is because both he and his beast are content with their current "situation" LOL. Not that I can really see him making Inuyasha his official mate. Like you said when you were contemplating mpreg, it wouldn't change their relationship all that much. This Sesshoumaru will never truly love this Inuyasha. But I definitely love this story! So glad to see you back and writing again. Keep it up!
I hope you go through with the MPREG. And I wouldn't mind the beastiality too. In fact, I would expect it, especially with their nature.
Thank you for the story. And again, more please!!!