Boss Music

Boss Music is used numerous times in the Kingdom Hearts series to indicate that the current battle is with a Boss. Most Boss Music is fast-paced and sends a theme of Evilness. Usually the same song would be used over different Boss battles to show the connection between them, i.e Shrouding Dark Cloud is associated with Heartless Bosses and Squirming Evil is used commonly for (Basic) Disney Bosses.

Awakening

 * Darkside = Dive into the Heart (Destati)

Destiny Islands

 * Darkside = Destiny's Force

Traverse Town

 * Leon = Night of Fate


 * Guard Armor = Shrouding Dark Cloud


 * Opposite Armor = Shrouding Dark Cloud

Wonderland

 * Card Soldiers and Crank Tower = To Our Surprise


 * Trickmaster = Shrouding Dark Cloud

Olympus Coliseum

 * Cloud = Shrouding Dark Cloud


 * Cerberus = Squirming Evil


 * Hades = Squirming Evil


 * Rock Titan = The Deep End


 * Ice Titan = The Deep End


 * Sephiroth = One-Winged Angel (from Final Fantasy VII)

Deep Jungle

 * Sabor = Having a Wild Time


 * Clayton and Stealth Sneak = Squirming Evil

Agrabah

 * Pot Centipede = Shrouding Dark Cloud


 * Cave of Wonders Guardian = Arabian Dream


 * Jafar (1st Battle) = Squirming Evil


 * Jafar (2nd Battle) = The Deep End


 * Kurt Zisa = The Deep End

Monstro

 * Parasite Cage = Shrouding Dark Cloud

Atlantica

 * Ursula (1st Battle) = Squirming Evil


 * Ursula (2nd Battle) = The Deep End

Halloween Town

 * Lock, Shock and Barrel = Spooks of Halloween Town


 * Oogie Boogie (1st Battle) = Squirming Evil


 * Oogie Boogie (2nd Battle) = The Deep End

Neverland

 * AntiSora = The Deep End


 * Captain Hook = Squirming Evil


 * Phantom = The Deep End

Hollow Bastion

 * Riku (1st Battle) = Scherzo Di Notte


 * Maleficent (1st Battle) = Squirming Evil


 * Maleficent (2nd Battle) = The Deep End


 * Riku (2nd Battle) = Forze del Male


 * Behemoth = The Deep End

End of the World

 * Chernabog = A Night on the Bare Mountain


 * Ansem (1st Battle) = Guardando Nel Buio


 * Darkside = Destiny's Force


 * Ansem (2nd Battle) = Guardando Nel Buio


 * World of Chaos = Guardando Nel Buio

Kingdom Hearts: Chain of Memories

 * Face It! - Unknown (Tutorial), Leon (Tutorial), Cloud, Monstro (Shadows)
 * To Our Surprise - Card Soldiers
 * Struggle Away - Guard Armor, Trickmaster, Parasite Cage, Darkside
 * The 13th Struggle - Axel, Larxene, Vexen, Lexaeus, Ansem (First Battle)
 * The Fight for My Friends - Hades, Jafar (Genie), Oogie Boogie, Giant Ursula, Captain Hook, Maleficent (Dragon)
 * The Force in You - Riku Replica
 * Graceful Assassin - Fake Marluxia
 * Scythe of Petals - Marluxia's Specter
 * Revenge of Chaos - Ansem (Final Battle)

Kingdom Hearts II

 * Tension Rising - Twilight Thorn, Demyx (First Battle), Beast The Nobodies;
 * The 13th Struggle - Axel, Luxord, Riku, Axel, Luxord,
 * Desire for all that is lost - Dark Thorn, Hydra, Pete in Timeless River (Second Battle), Volcanic Lord and Blizzard Lord,
 * Vim and Vigor - Shan-Yu, Cerberus, Captain Barbossa and Illuminator;
 * Dance to the Death - Thresholder/Possessor, Shadow Stalker, Prison Keeper, The Heartless;
 * Rowdy Rumble - Pete in Olympus Coliseum (First Battle), Pete (?), Lock, Shock, and Barrel, Shenzi, Banzai, and Ed, Hades (First Battle);
 * The Corrupted - Hostile Program, Storm Rider, Grim Reaper, The Experiment, Groundshaker;
 * The 13th Dilemma - Demyx (Second Battle), Xaldin, Xigbar, Saïx, Demyx, Xaldin, Xigbar;
 * The Encounter - Oogie Boogie, Hades (Second Battle), Scar, Jafar (Genie), Master Control Program and Commander Sark;
 * Disappeared - Xemnas
 * A Fight to the Death - Xemnas (Armor);
 * Darkness of the Unknown - Xemnas (Dragon), Inexistent World;
 * Sinister Shadows - Battle of the 1000 Heartless, The Nobodies and Sark.

Kingdom Hearts Re:Chain of Memories

 * Hand in Hand - Leon (Tutorial)
 * Go For It! - Cloud
 * Lord of the Castle - Marluxia's Angelic
 * The 13th Struggle - Zexion
 * Revenge of Chaos - Ansem (Tutorial)

Kingdom Hearts II: Final Mix

 * The 13th Reflection - Vexen, Lexaeus, Zexion, Marluxia, Larxene,
 * The Other Promise - Roxas
 * Rage Awakened - Terra

Kingdom Hearts Birth by Sleep

 * Rowdy Rumble - Lucifer