All characters:
Complete the Asia chapter with Kyo at level 10. Then, hold L1 + L2 + R1 +R2 while choosing Chris at character selection screen. All characters, including Orochi will now be selectable.

Orochi Iori:
Successfully complete all chapters. Then, hold L2 + R2 and choose Iori at the character selection screen.

Orochi team:
Successfully complete all chapters. Then, hold L2 + R2 and choose all New Face Team members at the character selection screen.

Saishu Kusanagi:
Successfully complete all chapters. Then, hold L1 and choose Kyo at the character selection screen.

Sendo Siblings:
Successfully complete the Disease chapter. Then, hold L2 + R2 and choose any Art of Fighting team member at the character selection screen.

Souiji Kusangai:
Successfully complete the Souji and Aoi chapters. Then, hold L1 and choose Kyo at the character selection screen.