Sesshoumaru is one of those weird cases. He's wearing what looks like a furisode type of kimono (aka the long sleeves) but the thing is that in real life those kimono are only worn by women, and young women at that. (maximum age around 20)
I would say just find any accurate kimono pattern (beware though, there's many inaccurate ones out there!) and then modify in the extra sleeve length, which should be very easy to do.
Real kimono have no shoulder seams, but there is a back seam because the body of the garment is basically one left and one right side panel. There's also the okumi panels to have the garment overlapping enough so you can close it. Most pieces should be square shaped.
I would recommend looking around on the old (now closed) Immortal Geisha forums
for a lot of good knowledge. Best of luck with your cosplay!