*Small rant about Sessrin being canon* Please ignore this post if you are pro sessrin.
People keep saying Sessrin is canon because of Rumiko Takahashi's involvement in the Yashahime sequel.
Did she design Moroha, Setsuna, and Towa? Yes but she also designed the characters for the Inuyasha video games and those are not canon. She also designed the twins without a mother in mind so no, she did not know they would be Rin's children.
She also drew a "sessrin" family to promote the Yashahime series but that doesn't mean anything either.
She drew this image to promote the first Inuyasha film when the movies are considered not canon.
There's also the fact that she stated that she saw Sesshomaru as Rin's hogosha (guardian) in an interview.
Also nothing in the original manga implied that there was romance between them, even at the end Sesshomaru was still looking after Rin by sending her gifts such as a kimono in the last chapter (558.)
And as much as I love Rumiko Takahashi, she has her flaws and was likely only in on the idea of a sequel for the money. You can argue that the sequel wasn't that successful but tons of new merch was made in celebration for it and attention was brought back to a series that died in 2012. I'm sure she made a profit from this dumpster fire.
This will probably be my last post on the Yashahime series so thanks for reading. Feel free to add anything if you want.