Ii Naotora (井伊 直虎, d. 12 September 1582) was a daimyō of the Sengoku period and head of the Ii clan, a feudal samurai clan of medieval Japan. There are two theories regarding Naotora's identity: The classical theory from Edo period stated Naotora was Jirō Hōshi daughter of Ii Naomori, the eighteenth head of their clan. She was primarily the head of Ii clan and retainer of the Imagawa clan. The second theory was that Ii Naotora was actually a son of an Imagawa clan retainer named Sekiguchi Ujitsune (関口氏経). According to this theory, the son of Ujitsune became temporary head of the Ii clan until Ii Naomasa, the son of Ii Naochika, reached adulthood and could inherit the position.
Source: “Ii Naotora”, English Wikipedia (CC BY-SA 4.0), excerpt