The King of Fighters XI/Mai Shiranui
A KOF/Fatal Fury mainstay and fan favorite, Mai Shiranui was surprisingly absent from the Arcade release of KOF XI.
But in the PS2 version (and the Japanese PS3/PSN rerelease of that version),
Mai is one of the 7 characters included as a bonus for players to unlock by completing certain challenges in the Challenge Mode (Challenge #20, in her case.)
Like most of the other PS2 bonus characters, her moveset and appearance are based off her inclusion in Neo Geo Battle Coliseum.