Complete the indicated character's Story mode to unlock the corresponding character:

Goemon Ishikawa: Successfully complete Magoichi's story
Hanzo Hattori: Successfully complete Tadakatsu's story
Hideyoshi Hashiba: Successfully complete Nobunaga's story
Inahime: Successfully complete Tadakatsu's story
Keiji Maeda: Successfully complete Magoichi's story
Kunoichi: Successfully complete Yukimura's story
Masumune Date: Successfully complete Kenshin's story
Mitsuhide Akechi: Successfully complete Nobunaga's Second story
Noh: Successfully complete Nobunaga's story
Ranmaru Mori: Successfully complete Nobunaga's Second story
Shingen Takeda: Successfully complete Yukimura's story
Tadakatsu Honda: Successfully complete Yukimura's story
Yoshimoto Imagawa: Successfully complete Tadakatsu's story