Azai Nagamasa is the daimyo of the Azai clan, husband of Oichi, brother-in-law to Oda Nobunaga and an ally of Asakura Yoshikage. He has a sister named Kyogoku Maria.
He is only mentioned in Sengoku BASARA 3 within Oichi's dialogues, indicating his death was a stepping stone to her own fall from grace.
A former ally of Oda Nobunaga, now rebelling against him. He is a man fighting for justice and vows to destroy anybody who creates chaos, namely Nobunaga. Wields a long sword and a folding buckler. His fighting style and mannerism are similar to that of a typical superhero, primarily the Metal Hero Series. He's also often seen roughly telling Oichi to be quiet or stop crying, only to shyly declare his love, making him a male tsundere. He is playable in Sengoku Basara 2 Heroes.
His story revolves around ridding Japan of the chaos, preferably Nobunaga, and his relationship with Oichi which started out with love, then turn to hatred and eventually leads back to loving her again. Nagamasa's story can be looked at a tokusatsu point-of-view due to certain elements of the genre present. He is the husband of Oichi.
And he is reprised by Christopher Bevins in the English dub and Koji Tsujitani in the Japanese dub.