At the character selection screen, highlight the normal version of one of the following fighters, then hold L1 and press any button:

Evil Rugal Berstein
'95 Kyo
Real Bout 2 Terry Bogard
Real Bout 2 Andy Bogard
'94 Joe Higashi
'94 Ryo Sakazaki
'94 Robert Garcia
'94 Yuri Sakazaki
Evil Yashiro Nanakase
Evil Shermie
Evil Chris
Real Bout 2 Mai Shiranui
Real Bout Bout 2 Billy Kane