Kamibeppu Kunai-shōyū served as a bushō during the Sengoku period. He was a retainer of Hyūga-Itō clan. His title means Assistant Vice-Minister of the Sovereign’s Household while his real name is unknown. He was the steward of Kiyodake and served as the lord of Kiyodake Castle in the Miyazaki District of Hyūga Province in Kyūshū.
According to historical records of Hyūga, Kunai-shōyū, together with Nagakura Bankurō, served as lords of Kiyodake Castle. In 1551, during the Siege of Mei Castle, Kunai-shōyū participated along with Nagaike Chikugo and others.
In 1572, at the Battle of Kizakibaru, Kunai-shōyū served along with Bankurō in the Itō army under the command of Itō Sukenobu and Itō Sukeyasu. In this battle, the Itō army fell to the Shimazu forces. After Kunai-shōyū learned that Bankurō had been killed in action, he felt ashamed of himself and returned to the battlefield, where he also perished. He was forty-one years old.