The Last Blade/Secrets

Neogeo
At the character selection screen press 6 Times  3 Times  4 Times.
 * On Arcade version only unlocks Akatsuki
 * On Home version unlocks both Akatsuki and Kagami

PlayStation
Finish the game once, then go to the character select screen and press psx: L1 + psx: L2 + psx: R1 + psx: R2.

Time Attack Mode
Insert coin, hold +++, then press Start.

EX Mode
In Mode Selection highlight Speed 6 times then highlight Power  3 times then highlight Speed  4 times.