There are 26 music themes to unlock:
-16 of the music themes are for obtained by playing on each of the team’s stages.
-1 music theme is for the destroyed arena which you will hear in arcade mode.
-1 music theme is Antonov’s theme, which again is heard in arcade mode.
-1 music theme is for the giant KoF arena. You’ll have to play on this stage in VS mode, because Antonov’s theme plays instead when you fight him in arcade mode.
The other 7 themes are heard by having certain character fight each other. This can be done in either arcade or versus. Here are the secret themes and the characters needed for them:
-Kyo vs Iori: New Order -KOF XIV version-
-Terry vs Geese: Soy Sauce for Geese -KOF XIV version-
-Athena vs Kensou: Tachi bou ke (with lyrics)
-Ryo vs King: Micha iya -KOF XIV version-
-Kim vs Chang (or Choi): Seoul Road -KOF XIV version-
-Ralf vs Clark: Ikari -KOF XIV version-
-Kula vs Angel: Ice Palace -KOF XIV version-