This guide will help you unlock all the secret characters in The Bouncer.
Black-Hooded Sion: Complete Survival Mode once. Then at the character selection screen in Versus or Survival Mode, highlight Sion, hold L1+L2+R1+R2, and press X.
Dauragon Mikado: Defeat Dauragon Mikado in Story Mode.
Dominique: Watch the scene where Dominique destroys the PD-4s in Story Mode.
Echidna: Defeat Echidna in Story Mode.
Kaldea: Defeat Kaldea in Story Mode.
Leann: Use Kou and complete Story Mode. At the end Leann will fight you, defeat her.
Maskless Mugetsu: Defeat Maskless Mugetsu in Story Mode.
MSF Kou: When playing the game as Kou, you'll encounter a part where he is infiltrating the Mikado building as a MSF solider. Once you conplete the game highlight Kou, hold L1+L2+R1+R2, and press X at the character selection screen in Versus or Survival Mode.
Mugetsu: Defeat Mugetsu in Story Mode.
One-Armed Dauragon: Defeat One-Armed Dauragon in Story Mode.
Overall Dauragon: Defeat Overall Dauragon in Story Mode.
PD-4: Defeat PD-4 in Story Mode.
Shirtless Dauragon: Complete Story Mode two times. On your third game after you defeat Overall Dauragon, you'll have to face Dauragon again for the last time. He's unlocked once you defeat him,
Wong Leung: Use Volt or Kou in Story Mode but use Sion to defeat Dauragon. Then defeat Wong Leung in Sion's flashback to unlock him.