After Nagayoshi's death, the three men emerged as custodians of the successor Yoshitsugu MIYOSHI who was still a child and all of Nagayoshi's brothers were deceased and collaborated with Hisahide MATSUNAGA, another Miyoshi commander wielding similar power, in the assassination of Yoshiteru ASHIKAGA (Eiroku no hen).
三好氏の当主三好長慶の死後、後継者の三好義継は幼く、長慶の弟達もまたこの世を去っていたため、義継の後見役としてこの三名が台頭し、三好氏の重臣として同じく権勢を振るっていた松永久秀と共に足利義輝の謀殺（永禄の変）に携わるなどした。