Board Thread:General Discussion/@comment-29619328-20160813152202/@comment-25593389-20170110105834

Yeah, you want fact : rangiku said "I know you're from a lesser branch but if the head of the shiba house continue to act in this manner..."

Also you can also use other language translations (french here) : "Je sais que vous êtes que d'une branche, mais si le chef du clan Shiba se comportait comme ceci, cela affecterait l'honneur de la maison mère"

Also if you refer to other wikia, still french, it's said "Chef du clan Shiba" in previous occupation.

--- FutureEeveeKing13 : If the main clan had no descendant the one who would take the head of the family would be from a branch. Also it was never stated that Kaien and his siblings were from the main family, just that they were the current leaders of the family.

On the countrary, it was more or less stated than Isshin was their uncle, but in that case they can only be from a branch, because by seniority if isshin was born as a member of a branch, then his brother/sister (parent of kaien and his siblings) would also be from the branch. Thus the children would be from the branch family too.