Fight as Tohma Kuki:
Successfully complete story mode with Seishiro Kuki.

Fight as Mikoto:
Successfully complete story mode with Haomaru.

Fight as Yuda:
Successfully complete story mode with Mikoto.

Fight as Minto:
Successfully complete story mode with Ran Po.

Play as Daruma:
Successfully complete story mode with Haito Kanakura.

Play as Tashon Mao:
Successfully complete story mode with Garyo The Whirlwind.

Play as Oboro's Amazons:
Successfully complete story mode with Saya.

Play as Iga Ninjas:
Successfully complete story mode with Hanzo Hattori.

Play as Samurai:
Successfully complete story mode with Jin-Emon Hanafusa.

Play as Brute:
Successfully complete story mode with Jushiro Sakaki.

Play as Mugenji:
Successfully complete story mode with Yaci Izanagi.

Unlock all but one hidden character:
To unlock all but one of the other hidden characters (they are all clones) successfully complete story mode with all the starting/default characters, except Rinka Yoshino.

Fight as "Ultimate" Seishiro Kuki:
Successfully complete story mode with all the characters, both hidden and default. He uses Tohma Kuki's and his own sword.