Karō (家老, house elder) were top-ranking samurai officials and advisors in service to the daimyōs of feudal Japan.
The famous samurai tale, Kanadehon Chūshingura, describes events involving a karō.
Two to a few Karos are in the clan administration in a collegial system, but faction conflicts often occur in connection with political reforms and succession issues.
It was a classic scene, and there were political disputes such as the fact that the clan theory was divided into two and led to a blood-washing conflict, and that the feudal lord was forced to retire with the fall of the reformist elders.
Basically, he was allowed to stay away from home because of illness or old age, and remained in the post of a senior until he died once he took office.