The Oshu Kira clan came under jurisdiction of the Hojo clan through a marriage of expediency, in the similar manner to the Kogakubo, coaxed and became a puppet player of the Gohojo clan who had become the ruler of the Kanto region.
関東の覇者となった後北条氏に取り込まれて傀儡化した古河公方とともに、こちらも政略結婚を通じて北条氏の傘下に入った。