The feudal lords who the samurai served under.
Each samurai had a lord in which he served. The Daimyo were known for their skill as generals and military leaders. Following the shogun, the daimyo were the most powerful rulers from the 10th century to the early 19th. The daimyo were only subordinate to the Shogun and only one man at a time could be Shogun. There were many daimyos all across Japan, but there was only one Shogun at a time. The samurai who had no lord were known as Ronin.