Bonus characters - Successfully complete the indicated task to unlock the corresponding character:

Azai Nagamasa: Successfully complete Wei Story mode Stage 6.

Cao Cao: Successfully complete Wei Story mode Stage 7.

Da Ji: Successfully complete all stages in the game, including the Gaiden stages.
Da Qiao: In Wu Story mode Gaiden 5, meet Da Qiao before the enemy does.
Dian Wei: Successfully complete Wei Story mode Stage 7.

Fuuma Kotaro: In Wu Story mode Gaiden 2, defeat him after all supply troops have reached your HQ.

Gan Ning: Successfully complete Wei Story mode Stage 6.
Guan Ping: Successfully complete Sengoku Story mode Stage 1.
Guan Yu: Successfully complete Shu Story mode Stage 7.

Honda Tadakatsu: Impress him in all Story modes in Gaiden 7.
Huang Gai: Successfully complete Wei Story mode Stage 5.
Huang Zhong: Successfully complete Sengoku Story mode Stage 1.

Imagawa Yoshimoto: In Wei Story mode Gaiden 4, prevent all ploy troops from entering the village.
Inahime: Successfully complete Wu Story mode Stage 5.
Ishida Mitsunari: Successfully complete Wei Story mode Stage 2.

Jiang Wei: In Shu Story mode Gaiden 2, succeed in initiating Jiang Wei's ambush plan.

Kunoichi: In Wu Story mode Gaiden 4, successfully escort all peasants.

Ling Tong: Successfully complete Sengoku Story mode Stage 5.
Liu Bei: Successfully complete Shu Story mode Stage 8.
Lu Bu: Impress Lu Bu by defeating him in all Story modes Gaiden 8.
Lu Meng: Successfully complete Wu Story mode Stage 3.
Lu Xun: In Sengoku Story mode Gaiden 3, successfully escort Lu Xun to your HQ.

Ma Chao: In Sengoku Story mode Gaiden 2, make sure that all peasants escape and Ma Chao survives.
Meng Huo: Successfully complete Shu Story mode Stage 4.
Miyamoto Musashi: In Shu Story mode Gaiden 6, successfully open the dam and keep all the yellow swordsmen alive.
Mori Ranmaru: Successfully complete Wu Story mode Stage 1.

Naoe Kanetsugu: Successfully complete Sengoku Story mode Stage 7.

Nene: In Wei Story mode Gaiden 3, defeat the two Nene clones within 4 minutes after their appearances.

Oichi: Successfully complete Wei Story mode Stage 6.
Okuni: Successfully complete Sengoku Story mode Stage 3.
Orochi: Unlock all characters besides Orochi.

Pang Tong: Successfully complete Wei Story mode Stage 4.

Saika Magoichi: Successfully complete Shu Story mode Stage 2.
Sanada Yukimura: Successfully complete Shu Story mode Stage 3.
Shima Sakon: Successfully complete Wu Story mode Stage 3.
Sima Yi: In Sengoku Story mode Gaiden 6, foil Sima Yi's strategy by killing the two retreating Orochi generals.
Sun Jian: Successfully complete Wu Story mode Stage 7.
Sun Quan: Successfully complete Wu Story mode Stage 7.
Sun Shang Xiang: Successfully complete Wu Story mode Stage 5.

Tachibana Ginchiyo: Successfully complete Shu Story mode Stage 1.
Taishi Ci: Successfully complete Wu Story mode Stage 2.
Takeda Shingen: Successfully complete Sengoku Story mode Stage 7.

Uesugi Kenshin: Successfully complete Sengoku Story mode Stage 7.

Wei Yan: Successfully complete Shu Story mode Stage 3.

Xiahou Dun: Successfully complete Wei Story mode Stage 4.
Xiahou Yuan: Successfully complete Wei Story mode Stage 4.
Xiao Qiao: Successfully complete Wu Story mode Stage 3.
Xu Zhu: Successfully complete Wei Story mode Stage 1.

Yuan Shao: Successfully complete Shu Story mode Stage 5.
Yue Ying: Successfully complete Shu Story mode Stage 2.

Zhang Fei: Successfully complete Shu Story mode Stage 7.
Zhang He: In Wei Story - Gaiden 2, successfully rescue Zhang He and defend the HQ.
Zhang Jiao: Successfully complete Sengoku Story mode Stage 3.
Zhou Tai: Successfully complete Wu Story mode Stage 6.
Zhou Yu: Successfully complete Wu Story mode Stage 1.
Zhu Rong: Successfully complete Shu Story mode Stage 4.
Zhuge Liang: Successfully complete Shu Story mode Stage 7.
Zuo Ci: Finish all four Story modes.