Masao Hiraishin (避雷針正夫, Hiraishin Masao) is a Shinigami and the deuteragonist and later an antagonist of the series. He is also the cousin of Kōtaishi Hiraishin and Masanori Hiraishin, the grandson of Masayoshi Hiraishin, the nephew of Masaru Hiraishin, and the son of Masato Hiraishin. At the beginning of the series he was the lieutenant of the Second Division under Masaru Hiraishin. He later defected along with the Seventh Division captain to join Masaru's Army.