Quote Originally Posted by Werecanary
Which could be found...?
It's on KH Final Mix OST, it can't be found on the ordinary KH OST. Kingdom Hearts: Final Mix soundtrack has 4 songs:

1) One Winged Angel from FFVII (the battle against Sephiroth)
2) Night on Bald Mountain (the battle against Chernabog)
3) Disappeared (the battle against an Unknown, only in KH: FM)
4) Another Side (Deep Dive special ending, only in KH: FM)