- Death: 1570
- Other name: Endo Kizaemon
Naotsune served Asai Nagamasa and was a leading Asai retainer known for his bravery. He was with Nagamasa when the latter first met Oda Nobunaga. That night Natsune approached Nagamasa to ask permission to kill Nobunaga, saying by way of explanation that he was clearly a dangerous man (Nagamasa refused to allow him to carry out the deed). Naotsune was one of the few Asai retainers to oppose breaking the Asai alliance with the Oda when Nobunaga marched against the Asakura (1570). Naotsune fought hard at the Battle of Anegawa (1570), killing some ten Oda warriors. He was himself slain while attempting to reach Oda Nobunaga's headquarters, we are told, by Takenaka Kyusaku, a younger brother of Takenaka Hanbei.
- Initial text from Sengoku Biographical Dictionary (Samurai-Archives.com) FWSeal & CEWest, 2005