Play as Master and Uranus:

While the options are flying on to the Title screen, press this combination VERY QUICKLY for Player 1: R1, L2, WK, L1, R2, SK. You should hear a sound and the cursor turning blue to indicate that it worked.

Play as Vermillion and Sho:

Do the code above first, then repeat the process with this combination for Player 2: SK, R2, L1, WK, L2, R1. You should hear a sound, with the cursor turning from blue to red this time.

The new fighters will appear in the Random box on
the Character Select screen. Hold Taunt to slow
down the character cycling. For an easier way to
enable all fighters, edit this registry entry: [HKEY_LOCAL_MACHINE\SOFTWARE\GameBank\Toshinden2]
"GOBUKU"=hex:02,00,00,00