Board Thread:Naruto Discussions/@comment-28568301-20181025153300/@comment-26636534-20181025175119

If I recall correctly, Kaguya is from the main family line of the Otsutsuki clan. I don't think she was ever referred to as the leader of the Otsutsuki clan. The closest thing to a leader she could be, is the leader of the branch family of the Otsutsuki on earth.