The following codes must be entered at the Character Select screen:

Lord of Chaos:

Press Up, Up+Left, Left, Down+Left, Down, Triangle + X.

Minion of Chaos:

Press L1 + L2 + R1 + R2 + Up + X.

Minion of Order:

Press Left + Square, Right + Circle.

Strahd:

Press Up, Right, Down, Left, R1, R2, L2, L1.