After defeating the Prince Nagaya in the Conspiracy of Nagayao, along with Muchimaro (Dainagon [chief councilor of state]) and Fusasaki (Sangi [councilor]) who had already become a court noble, Umakai and Maro also became sangi, and four brothers occupied the power among the nine court nobles and they played a political role in the Imperial Court from 729 to 737.
長屋王の変で長屋王を追い落とした後、すでに公卿となっていた武智麻呂（大納言）・房前（参議）に加え、官人の推挙により宇合・麻呂も参議となり、9人の公卿の内四兄弟で4人を占め729年から738年の間朝廷の政治を担った。