Before selecting your player, hold the L button and press left or right on the digital pad. The rotating character pictures will change color indicating the trick worked. Keep holding L when you select your character.

To play as the final boss, press A, B, Right, Left, Right, Left, Down, Down, up, Up at the title screen.

To play as the sub-boss, press Up, Up, Down, Down, Left, Right, Left, Right, B, A at the title screen.

When you get knocked down, keep on pressing any of the c-buttons and you'll get about two hits worth of health.

Create a character and proceed to train it. Keep training until you have 90 moves for that Character. Now go and create a new character. There will be two new bodies to choose from; one male and one female.

Beat the game in "TAG TEAM" Mode with the difficulty set to VERY EASY with only one character (don't let anyone join you) in under 21 minutes. You'll get a new stage next to the ring with a Tokyo Theme to it.

Enter the "Play as Reiji" code. When your life bar is about one-third full, press R and L together and he should transform into Yami or Hikiri.