Battle Theme Music

""Sometimes, music soothes the beast. Sometimes, it just gives it a kick-ass battle tune to fight to.""

- Troper Glazed

In video games, battles are typically indicated by upbeat or tense music to give a hint of danger. Battle music tends to pop up the most in Role Playing Games, where there are often battle screens separate from the rest of the action. Battle music doesn't usually appear in games where you fight and explore on the same plane of action, but it may fade in when you get close to a threat, particularly in more recent games.

Several different types of battle music may appear:

Shifting Battle Music - Because you might get sick of the battle theme if it's the same throughout the game, some games may employ several different "normal" battle themes which change throughout the game.

These themes may be:
 * Progressional: As you progress through the game, the battle theme may change at certain milestones. For example, most of the Breath of Fire games did this.
 * By Dungeon: If the battle music is merely a remix of the dungeon music, each dungeon may have its own music. This is fairly rare, through, because of the extra work involved. The Neverwinter Nights series does this.
 * Situational: A different, more tension-filled battle theme may play in different situations, such as getting ambushed by the enemies. Some of the Grandia games did this, for example.

Boss Battle Music - Most games have a separate battle theme for the Boss Battle, including games which aren't RPGs. This is usually a tense, action-packed theme.

Different Boss Battle musics may play for:
 * Normal Boss Battle - The battle theme for 'normal' bosses or minibosses. Some games may have a few different 'normal' Boss themes.
 * Major Boss Battle - A more dramatic theme for the more difficult or unique bosses. Usually used for a Climax Boss. May overlap with the Villain Battle Theme.
 * Villain Battle - The battle theme for major story villains, which may serve as their Leitmotif, or be a Boss Remix thereof. This is usually lighthearted and silly for the Goldfish Poop Gang or Quirky Miniboss Squad, but more serious bosses such as The Dragon or Big Bad will have more tension-filled battle themes.
 * Final Boss Battle - The battle theme for the Final Boss of the game. If the Final Boss has multiple forms (as they usually do), each form will have its own theme music. The first form may use the Major Boss or Villain Battle theme for that particular Big Bad, but later forms will be unique. The very last battle music may be marked by the use of organs, ominous choir, or extremely tense rock music.

Battle Fanfare - The victory fanfare that plays at the end of the battle. Some games have no fanfare at all for normal battles, and switch back to the 'dungeon' music instantly on completion of the battle. These games may sometimes have them for completing the Boss Battle, though.

As for games with battle fanfares, they tend to come in two styles:
 * Final Fantasy style: The fanfare plays, followed by a triumphant theme which lasts until the 'battle screen' is exited.
 * Dragon Quest style: A short fanfare is played, after which the dungeon music starts up again.

See also Orchestral Bombing for the movie version.

Action Adventure

 * The Legend of Zelda:
 * Surprisingly averted in the first The Legend of Zelda. None of the enemies or bosses, not even Ganon, has a battle theme.
 * The Adventure of Link and A Link to the Past have each a particularly unnerving boss battle music. The Final Boss however, has a better one, and the A Link to the Past one is later used for Phantom Ganon in The Wind Waker.
 * Ocarina of Time has five boss battle themes. Two for the final battle, the ones fought on Death Mountain (dungeons 2 and 5) the other bosses, and the minibosses. Interestingly, the Death Mountain boss theme was remixed for Stallord in Twilight Princess. And they all rock.
 * From The Wind Waker onwards, each boss (at least in the console 3D games and, to an extent, Spirit Tracks for the DS) had a unique boss theme. Twilight Princess goes as far as having a unique theme for the minibosses.
 * The boss battle music in Twilight Princess often got a triumphant version of the game's overworld theme when you're in the process of exploiting the enemy's weak spot with some well-aimed sword strikes. It used one song for the bosses before the fourth dungeon, and another for the ones after. The switch happened right in the middle of the fourth bosses's fight. Also in the game, there is also a tense 'You're Losing' mix when Ganondorf seems to get the upper hand when you've locked blades with him.
 * Castlevania loves this: in Aria of Sorrow there's separate boss music for Julius (a combination of two old tunes, "Don't Wait Until Night" and "Heart of Fire") and in Dawn of Sorrow  uses Dracula's fight music, "Dance of Illusions".
 * Aria of Sorrow also had a separate boss theme for fighting and  There is also both a regular boss theme used for most bosses, and a major boss theme used for Creaking Skull and Balore.
 * In Symphony of the Night there is Festival of Servants for Normal boss battles, Death Ballad for Major boss battles like Death or Shaft, Enchanted Banquet for Medusa and Succubus, Dance of Illusions for Dracula in the intro, Blood Relations for, and Black Banquet for the Final Boss against Dracula again.
 * Order of Ecclesia has a regular boss theme (Symphony of Battle), a theme for the more difficult bosses (and Jiang Shi) (Dissonant Courage), a theme for the bosses fought inside Dracula's Castle (Chamber of Ruin), two villain songs (Sorrow's Distortion and Lament to the Master) and the Dracula battle music (Order of the Demon).
 * Dracula usually has at least two boss themes, one for his normal form, and one or more for his One-Winged Angel forms.
 * Cave Story generally has one of two themes: The light, fast Normal boss theme ("Gravity") and the deep, heavy Major boss theme ("Eyes of Flame"). The normal final boss and the Perfect Run Final Boss both have "The Last Battle" as their theme. Only three bosses get their own unique themes: The Core ("Oppresion"), the One-Winged Angel form of the Big Bad (the oddly playful and repetitive "Charge"), and, oddly enough, a Giant Space Flea From Nowhere ("Run!", recycled as normal BGM during a couple of action scenes).
 * The Big Bad has two unique themes for the first two forms: the second is "Zombie", which is darker and even more repetitive.
 * Used to great effect in Shadow of the Colossus; the music becomes a lot richer and more intense when you climb onto the titans. As the whole game consisted of boss battles, the change of music during the battle is one of the most memorable parts of the game.
 * Each boss in La-Mulana has a unique boss theme.
 * The SNES version of Prince of Persia has four battle themes: for Mooks, normal bosses, the Giant Space Flea From Nowhere in Level 17, and the Final Boss.

Adventure Game

 * Hype The Time Quest has two themes used in boss battles. These tend to fade as the titular character moves farther away from the boss.

Beat'Em Up

 * God Hand goes the extra mile: all minibosses and regular bosses have their own theme music, and when you fight the demon forms of Elvis and Shannon, their regular boss music gets remixed.
 * Mad World uses four themes for its regular bosses: "MADWORLD" (for Little Eddie, Jude the Dude, Shogun and the Shamans), "Bang" (for Von Twirlenkiller, Frank and the Masters), "Death and Honor" (for Yokozuna, Kojack and Martin) and "You Don't Know Me" (for the female bosses Rin Rin and Elise). The final boss,, gets two Villain Song themes: "Look Pimpin'" for the first half and "So Cold" for the second.
 * The arcade version of Double Dragon features a standard theme for the first three bosses. For the final boss, it plays the opening title theme instead.
 * The NES version of the first game lacked the boss theme, but still plays the main theme during the final battle until Jimmy shows up (where it switches to the Mission 1 theme).
 * In the arcade version of Double Dragon II, each boss has a unique theme music. In the NES version, a generic boss theme (the same tune that was used for Abore, the Mission 2 boss, in the arcade version) is used for all the bosses, except the player's evil clone (who uses a different boss theme than the one in the arcade version) and the final boss (which was later used in the GBA version as the theme of Raymond, Willy's bodyguard).
 * In both, the arcade and NES versions of Double Dragon III, every boss has his own theme music as well, although some of the bosses in the NES version are different (namely the ones in Mission 2 and 4) and other bosses (like Ranzou and the final boss) have different theme music as well.
 * River City Ransom has four distinct boss themes: a "middle boss" theme (the standard boss theme), a "big boss" theme (played only during two specific boss battles), the Dragon Twins theme (actually a rendition of the Double Dragon theme) and the final boss theme.
 * The original Streets of Rage has "Attack the Barbarian" as the standard boss theme and "Big Boss" for the battle against Mr. X.
 * The second game has "Never Return Alive" for the standard bosses, "Max Man" for Shiva and "Revenge of Mr. X" for the final battle.

First-Person Shooter

 * The Metroid Prime series has a unique theme for every major boss. Further, each area has a basic ambient tune that plays as long as you are exploring, while a special Battle Theme cuts in whenever space pirates show up.
 * The approach of a tank in Left 4 Dead is accompanied by this track, and it continues playing until the fight is over. During a Finale, a slightly modified version of the Tank theme plays, called "taank". The second "Boss Infected", the witch, also has her own score. The other, less dangerous "Special Infected" have shorter leitmotifs that play when they spawn or when they pin a player. There's also a variety of drum themes that play during a horde attack, and a special "slayer" theme that is mixed in when the player is engaging a horde. For Left 4 Dead 2, the horde music is even played by different instruments depending on the campaign, and the Concert finale has two rock remixes of the Tank theme.

Platform Game

 * Sonic 3 and Knuckles includes the following themes: Act 1 Boss, Act 2 Boss, Main Final Boss and Perfect Run Final Boss (Super Metal Sonic and Doomsday Zone).
 * Sonic Adventure 2 (and its predecessor, to a lesser extent) featured a unique boss battle theme, which repeated for most major bosses, with the game's Big Bad sporting a unique and particularly awesome one.
 * In Sonic the Hedgehog 2006, there's one boss theme for all of the hedgehog vs. hedgehog fights, and each of the game's Big Bads (Eggman in Sonic's story, Mephiles in Shadow's story, and Iblis in Silver's story) get their own theme, each of which gets remixed for their Final Boss fight. And then the True Final Boss gets a separate theme for both both phases of its fight.
 * Banjo-Kazooie and its sequel, Banjo-Tooie does this whenever you take on a boss with the battle music being a more intense version of level's background music.
 * Donkey Kong 64 does the same thing.
 * The Mega Man series is kind of a weird case: Each game has its own boss fight music for the robot masters, and depending upon the game there may be additional boss fight musics for fortress bosses or the final boss. However, robot masters are usually associated with the theme music that plays during their stages rather than the boss fights themselves, possibly as a result of naming the stages after their bosses.
 * Super Mario Bros:
 * The earlier 2D games give a theme for both the bosses and the minibosses. The exception is the very first one, which (like the first NES Zelda game) averts the trope entirely.
 * Bowser in particular, the main villain of the Super Mario Bros series, games always has a different boss battle theme in every game since Super Mario Bros 3. Of all of the battle themes he has, the ones from Super Mario Galaxy and Super Mario Galaxy 2 are by far the most impressive-sounding. In Super Mario 64, he gets an Ominous Pipe Organ remix of his theme for the final battle.
 * In Wario World, each boss has its own battle music.
 * In Wario: Master of Disguise, there are four battle themes: the normal boss theme, Count Cannoli's boss theme, Carpaccio's boss theme, and the final boss theme.
 * The original three Metal Slug games (including Metal Slug X) have a particularly memorable Boss Battle theme—"Steel Beast"—that actually progresses from game-to-game. In the original, it is in 5/8 time; Metal Slug 2 and X use the 6/8 "6 Beets" version; Metal Slug 3 has its own 7/8 version. Sergeant McNeil appropriates the "Assault Theme" from the first game, and the "Final Attack" theme is widely used for the game's final boss.
 * In Conkers Bad Fur Day, at least three bosses share a mainstream boss theme (in fact, there is a remix of it for the one fought in the ranch). The rest, however, have their own themes, except for The Final Boss who notably averts the trope entirely. When you fight him, all you hear is

Role Playing Game

 * Every RPG in existence.
 * Final Fantasy I has the same battle theme for everyone, from common enemies to the final showdown with Chaos.
 * Though when it was remade, they added a number of new pieces of music for Boss Fights, including an awesome Final Boss fight music for Chaos.
 * The Four Warriors of Light has additional "The Boss Turned Red" and "you're dying" music on top of the regular battle theme.
 * Final Fantasy XII has no 'normal' battle theme to speak of (the area music keeps playing), but goes crazy with the Boss Battle themes. There's 'Boss Battle', 'Clash of Swords', 'Battle Drum', 'A Speechless Battle', 'Esper Battle', 'Desperate Fight', and 'The Battle for Freedom.'
 * There's more than that. There's also 'Upheaval', and 'Boss Battle' is chopped up, with different sections of it playing in different orders for almost every boss.
 * Seiken Densetsu 3 has no battle music for normal enemies at all, they just appear randomly on the screen, but it has separate songs for nearly all bosses (which may also be used elsewhere), and those are a LOT.
 * Very well done in Xenosaga Episode III, where almost every boss had his personal battle theme.
 * Sadly, this was very poorly done in 'Xenosaga ep. I, where every boss had the same generic battle theme. In fact, every battle of the game, with the exception of the last battle, used the exact same music.
 * The majority of the story bosses in Xenoblade Chronicles use the same theme, though the songs from the cutscenes preceding them sometimes carry on into the fight, then are replaced by the usual boss theme once they finish. Another boss theme is used for all of the unique monsters and some of the story bosses as well, usually in situations where the party is making a comeback after getting roughed up by the boss in the previous cutscene.
 * Chrono Trigger had only one normal battle theme (not counting an unreleased track that didn't make it into the actual game), but had several boss themes. These included a Normal Boss, Major Boss, two Villain Battles (for Magus and Lavos, respectively), and two Final Boss Battles. The Ocean Palace, meanwhile, subverts this by not changing the music when a battle ensues.
 * The Ocean Palace theme was tense and badass enough to not NEED to be swapped out to suit combat.
 * The Pokémon Video Game series has developed this structure, including Boss music tracks for Gym Leaders, Rivals, the villain teams, certain Legendary Pokémon, and the "final bosses" (the Elite Four and Champion battles).
 * The number of different battle themes has exploded since the series' debut:
 * Red, Blue and Yellow have four: Wild Pokémon, Trainer, Gym Leader, Champion.
 * The remakes FireRed and LeafGreen gave battle music to normal Legendaries, Mewtwo, and Deoxys, the former two being a rearrangement of the normal Wild Pokémon music. In addition, the Elite Four used the Gym Leader music instead of the Trainer music.
 * Gold and Silver have nine: Johto Wild Pokémon, Johto Trainer, Team Rocket, Johto Gym Leader/Elite Four, Rival, Champion, and rearrangements of the Wild Pokémon, Trainer and Gym Leader themes from Red, Blue and Yellow. Crystal added one for the legendary beasts (Raikou, Entei and Suicune).
 * Also, the Johto wild Pokemon theme has two arrangements, one for day time, and one for night time.
 * HeartGold and SoulSilver, the second set of Video Game Remakes, have sixteen: rearrangements of all nine aforementioned Gold and Silver battle themes, two new unique and remake-exclusive battle themes for Ho-oh and Lugia, three separate rearrangements for the beast trio, a rearrangement of the Hoenn Weather Trio theme, and the Frontier Brain theme from Platinum. The ten themes present in Crystal also have 8-bit remixes via the GB Sounds key item, for a grand total of 26 themes. Arceus' theme from Diamond, Pearl, and Platinum also appears, but it is not used for any battles.
 * Ruby and Sapphire have eleven: Wild Pokémon, Trainer, Team Magma/Aqua Grunt, Gym Leader, Rival, Archie/Maxie (Magma/Aqua Boss), Legendary Pokémon, Regi trio, Elite Four, Champion, and the Deoxys theme. Emerald also added two more: Frontier Brain and Mew (the latter a rearrangement of the RBY Wild Pokémon theme).
 * Diamond and Pearl have fourteen: Wild Pokémon, Trainer, Rival, Gym Leader, Team Galactic Grunt, Team Galactic Commander, Cyrus, Dialga/Palkia, Uxie/Mesprit/Azelf, Legendary Pokémon (Heatran/Regigigas/Diamond and Pearl Giratina), Elite Four, Champion, Arceus . Platinum gave battle themes to Giratina, the Regi trio (again, a rearrangement), and Sinnoh Frontier Brains.
 * Black and White have: Wild Pokémon, Trainer, Rival, Team Plasma, Gym Leader, Gym Leader's Last Pokémon (which is an arrangement of the main theme), N, Battle Trouble (a song that replaces the incessant beeping when your Pokémon's low on health), Elite Four, Reshiram/Zekrom, Kyurem (an arrangement of Reshiram/Zekrom's battle theme), Final Battle with N, Ghetsis (the one with the "DENNIS" chanting), Battle Subway Trainer, Legendary Pokémon,, Strong Wild Pokémon (an arrangement of the normal Wild Pokémon battle theme that's used for special battles, like Zoroark), Champion, and High Ranked Battle Subway Trainer (an arrangement of the Champion theme from RBY) - bringing the grand total to nineteen battle themes. And Pokémon Black 2 and White 2 are sure to add even more.
 * Pokémon Colosseum has Friendly Battle, Normal Battle, Cipher Peon Battle, Cipher Admin theme, Miror B., Semi-final Battle, Final battle in a Colosseum (which is an arrangement of the Cipher Admin theme) and Final Battle. The battle with Nascour inverts it though; no music plays.
 * In Chrono Cross, the theme when the player fights Miguel is the same morose music that is played during the exposition. The penultimate boss battle is also only the one with a unique theme (besides the above-mentioned Miguel and ), while the actual final boss fight has no music at all and all the sound effects echo slightly.
 * Golden Sun has epic scores for its final bosses... and every other battle too.
 * Baldurs Gate 2 in an interesting example has a special song when fighting dragons. No other enemy type receives this particular kind of special score. Since Dragons are powerful and significant foes, they tend to warrant "boss" status, even if they aren't actually major parts of the story. (with one exception in To B)
 * Icewind Dale is interesting in that the climactic final boss music plays during the Big Bad's initial human Mook Maker form (which is actually rather weak). The actual final battle, which takes place a few levels later and pits your party against a 15-foot tall demon, has no background music at all. Conversely, the final battle of the Heart of Winter expansion pack has extremely epic final boss music.
 * Neverwinter Nights had four different sets of battle music (3 standard and 1 boss theme) for each region type in the game (i.e. city, forest, etc) as well as unique boss themes for Dragons,, and the final battle against Morag.
 * The entire Kingdom Hearts series has nearly as many Boss Themes as it does regular battle themes. This is especially prominent in Kingdom Hearts II, as the same boss theme is rarely played twice in a row.
 * Major Disney Villains have two themes that they generally use. Heartless and minor Disney villains (e.g. the Hydra) draw from a larger pool of mostly great themes. Organization XIII has three themes of their own, not counting the ones for Xemnas, Marluxia and
 * Several major plot characters have their own themes: the final bosses of each game,, , and (his theme, a remix of his Leitmotif, is also a huge Tear Jerker.) , appropriately, shares his theme with .  also has a remix of their leitmotif, and  has one that takes strong cues from the leitmotif of two related characters, going so far as to be a remix of them at times.  has one that mixes Fragments of Sorrow with yet another character's leitmotif.
 * Chernabog and Sephiroth, of course, have "Night on Bald Mountain" and "One-Winged Angel."
 * The final bosses of most of the games even use different themes for different phases of their battle (this being a series fond of marathon-length sequential final bosses.) Marluxia takes this up to eleven with three unique themes for his three-stage fight in Re:CoM.
 * The folks over at the Kingdom Hearts Wiki have put together a list of what music plays for what boss here.
 * Eternal Sonata did this well. Let's see... you got the battle theme, Four boss themes, The Villain theme, the next-to-last battle theme, the Final Battle theme (Which is an awesome remake of Frederic Chopin's Revolution, with a ton of string instruments and an epic choir thrown in for the hell of it) and, for Ps3 owners, there's an extra boss who has his own battle theme as well. That's 9 battle tracks in total.
 * The battle fanfare, "Well Done", starts triumphant before transitioning into a lighter theme that just repeats until you get past the reward screen (and any level up screens that may have been triggered).
 * Ys series: The later games and remakes tend to have multiple boss themes, eg, the dungeon end boss musics are different from the mid-bosses("Beasts as Black as Night" and "Shock of the Death God" in III), major or Climax Bosses have a special theme (eg "The Ordeal Becomes Great" in IV), and The Dragon (e.g. Dalles in II Eternal), Quirky Miniboss Squad(e.g. the Mages in V), and the Big Bad usually have their own unique theme, with variations for multiple forms.
 * Phantasy Star IV has a normal boss battle theme, a boss battle song for Zio and Lashiec (Laughter) and a boss battle theme for the 3 forms of Dark Force.
 * Almost every Tri Ace game plays some variation of the song Incarnation of the Devil for at least one of the battles with its bonus bosses.
 * Persona 3 has three boss themes: "Master of Shadows" for a Full Moon Shadow, "Master of Tartarus" for a Tartarus floor boss, and "Unavoidable Battle" for . Then comes the final boss battle and the near-legendary "Battle For Everyone's Souls", a Boss Remix of the Velvet Room theme "Poem For Everyone's Souls".
 * Persona 3 Portable adds the catchy "Danger Zone" battle theme for Tartarus Bosses while playing as the female protagonist.
 * The Answer adds two more: "Heartful Cry", for when, and "Darkness", for the final boss.
 * Persona 4 has fewer boss themes than its predecessor. Mid-Bosses use a modified version of Reach Out To the Truth. Character Shadows and Secret Bosses all use I'll Face Myself. and  use New World Fool.  uses The Almighty, and  has Fog and The Genesis for  two forms.
 * MARDEK has multiple Boss Battle themes, including, but not limited to, the basic Boss Battle, Muriance Battle, Saviours Battle, GdM Battle, Grand Boss, Secret Boss, Guardian Battle...
 * Baten Kaitos. Where do you even begin with this game? There's Chaotic Dance, which plays during the fights against Giacomo and his goons, Supreme Ruler of the Nine Heavens plays during the first two fights with Malpercio, Violent Storm for the final boss fight...and for all the other bosses, it alternates between Vitriolic a Stroke, The True Mirror ~ Guitar Version, Rumbling of the Earth, Condemnation of Darkness, and Glowing Cloud. Then there's the prequel, Origins, which has Chaotic Dance 2 for the Giacomo fights, Iconoclasm for the battles against the Dark Service officers, Poacher for the battles, Evidential Material for miscellaneous bosses, The Valedictory Elegy ~ Guitar Version for arena battles, Crystal Abyss for the fight against Wiseman, The True Mirror ~ Orchestral Version for the battle against, Ruinous Commander plays during the fight against . And finally, though it's not technically a boss theme, Le Ali Del Principio plays during the last part of the final boss battle.
 * The Last Remnant takes this trope and runs with it. There's plenty of bosses with personal themes, and there's around FIFTEEN battle themes. The best part is that they're in awesome hard rock-metal style.
 * The Paper Mario series have a music for the minibosses and then a singular theme for each boss, overlapping with the Leifmotif for major bosses. And all the themes are awesome.
 * Demons Souls doesn't have in game music aside from the bosses, who (save the Tower Knight and Penetrator) all have their own theme, including the Vanguard who serves as the tutorial boss.
 * Shadow Hearts games usually have a Normal Battle Theme and Boss Theme, which changes when the player reaches the halfway point (usually moving to another continent). Covenant also has unique, incidental themes for battles with enemies such as the Wolf Bouts, Astaroth, among others.
 * From Rance 5D on, the Rance has used rock music as a Final Boss theme.

Shoot'Em Up

 * The same theme is used on the three games in the Star Fox series with Star Wolf in (not counting the unreleased Star Fox 2 where it was different), and whenever the player controls Wolf, it is his Leitmotif.
 * The original game had different themes for each of the planet bosses (Corneria/Meteor, Titania, Fortuna, and Macbeth), a theme for space bosses, and a remix of the latter for the Venom bosses (both orbit and planetside).
 * The Touhou series does this in fine form - each boss in each game has her own theme music which is instantly recognizable. Some get more than one theme!
 * Iron Tank has a normal boss theme(at 3:28 in this clip) for tanks, trains, and other vehicles, and a different theme for stationary bosses such as base fortifications and long-range turrets.
 * Raiden IV alternates between the Raiden II and Raiden I boss themes.
 * R Type Final: Organic Boss, Mechanical Boss, Final Boss.
 * The Guardian Legend used more ominous or frantic boss music for the tougher bosses.
 * The standard boss theme in Ikaruga is "Butsutekkai", but the Chapter 2 boss uses "Recapture", a dark rearrangement of "Trial", and the Final Boss's third form uses a Theme Music Power-Up remix of "Ideal".

Stealth Action Game

 * Metal Gear:
 * The original game, Metal Gear 1987, has the standard boss theme ("Mercenary"), one for Metal Gear ("TX-55 Metal Gear") and the final boss theme ("").
 * Metal Gear 2 Solid Snake has four different boss themes played at specific battles: "Killers", "Battle Against Time", "Mechanic" (played specifically against mechanical bosses) and Night Sight's theme (the only BGM not in the official soundtrack).
 * Metal Gear Solid uses "Duel" for all the boss battles and "Escape" during the second phase of the Metal Gear REX battle and for the jeep battle with Liquid.
 * The GameCube version gave all of the bosses unique themes.
 * Metal Gear Solid 2 Sons of Liberty uses a self-titled theme for the battle against Olga Gurlukovich, "Yell 'Dead Cell'" for all the boss battles in the Big Shell and "Father & Son" during the battle against the mass-produced RAYs and later against Solidus Snake.
 * Metal Gear Solid 3 Snake Eater has a unique theme for each of the Cobras (with the exception of The End, where only ambient noises are played), as well Ocelot and Volgin. During the final battle against The Boss, an extended version of the intro theme, "Snake Eater", is played when the time limit is running out.
 * Metal Gear Solid Portable Ops has a unique theme for each boss. Null gets two boss themes, one for each battle with him.
 * Metal Gear Solid 4 Guns of the Patriots gives each boss a unique theme again. Gekkos get their own battle theme and Haven Troopers use a different theme during forced encounters. The fight against Suicide Gekkos uses the same theme as for the battle with Vamp. The final battle against Liquid Ocelot returns music from all the games (except Portable Ops) up to this point.
 * Metal Gear Solid Peace Walker has a unique theme for each boss, with Peace Walker getting two themes, one for each encounter. One of these is the main theme.

Survival Horror

 * In Resident Evil 2, the musics for the battles with each of Birkin/G's forms share a recurring theme, becoming more intense the more grotesquely it transforms. Each version of the theme is titled "The ____ Malformation of 'G'", where the blank indicates the order of the form ("First", "Second" and "Third").
 * Other multi-forms bosses in the series, such as Nemesis in Resident Evil 3 and Alexia in Code Veronica, also feature different renditions of their themes for their different forms.

Third-Person Shooter

 * The Mega Man Legends games have a unique song for every single boss fight.
 * Winback uses a different boss theme for each of the games major areas (Office Building, Factory, and Control Center), another theme for the penultimate boss, and a Theme Music Power-Up for the Final Boss.
 * PN 03 has two standard boss musics, one for robot bosses, the other for Reactor Bosses, and a few unique battle themes such as the Multi Mook Melee at the end of Mission 4, Orchidee's upgraded form, and the Final Boss's two forms.

Turn Based Strategy

 * Yggdra Union literally breeds battle themes. The game has a separate theme for ALL playable named characters and five generic ones that play for generic units, depending on their affiliation and rank. Which theme plays is decided by who is doing the attacking in the current battle.
 * And then there's Blaze Union and Gloria Union, which do much the same thing.
 * The Fire Emblem series generally uses the Normal, Major and Villain formula for boss themes, but Radiant Dawn deserves particular mention for having an absolute ton of Villain themes, with nearly every major storyline boss getting their own unique one, including an NPC you never get to fight outside of scripted cutscenes!  It even somewhat Inverts this by giving several late-joining (but extremely powerful) playable characters their own unique battle themes. And they are awesome.

MMORPG

 * Runescape has battle themes in dungeoneering. There are several different 'types' of dungeon (frost, abandoned, furnished, occult, warped). Every type of dungeon has 10 different battle themes, and a random track will play whenever you are in combat in daemonheim. On top of this, all of the 30 bosses for dungeoneering have their own theme tune, some of them are among the best music in the game.
 * What's more, both the standard combat themes and the boss music in daemonheim really suit the area/boss monster they play for.
 * Quest bosses generally have their own music as well. They are usually better (or at least more intense) than most of the games' music.
 * Vindictus primarily saves its battle themes for boss battles, with many of them being particularly awesome.

Real Time Strategy

 * Rise of Nations, interestingly enough, plays depressing orchestral tunes when you're losing a battle, and victorious fanfares when you're winning one.
 * Its Spiritual Successor, Rise of Legends, does the same thing.

Role Playing Game

 * As mentioned above, the Final Fantasy and Dragon Quest series employ their respective styles of fanfare.
 * The MOTHER series employs a more subdued version of the Final Fantasy style, with the first game going to silence after the fanfare and the other two going to a soft, ambient theme after the fanfare.
 * The victory tune for each Grandia game would change if you got a perfect battle.
 * Super Mario RPG and the Mario and Luigi series use the Final Fantasy style, while the Paper Mario games use the Dragon Quest style.
 * Pokémon has three variants of the Final Fantasy style, one for defeating and capturing wild Pokémon, one for defeating a Trainer, and one for defeating Gym Leaders and Elite Four.
 * Later games also add a fanfare for defeating members of the villainous team.
 * There are two for MARDEK: one for after regular battles, and one for after boss battles.
 * The fanfare in Chrono Cross is a reworked version of Lucca's theme from Chrono Trigger, interestingly enough. A bit unusually, the same fanfare plays when you recruit characters and at certain (usually triumphant) events in the story.

Turn Based Strategy

 * Yggdra Union does this for the damage calculation screen.
 * All games in the Star Control series had victory fanfares for each type of ship (upwards of 30), giving a specific feel for each of the races.
 * And of course, the (single) combat theme music in Star Control II is arguably the most memorable musical piece in the entire game (which is surprising, considering the amount of unique music themes this game contains).

Action Adventure

 * 3D The Legend of Zelda games deserve a mention for their normal battle music, which only activates gradually when an enemy is nearby. This gives it a secondary function of a sort of Spider Sense, if you will, since you'll sometimes know when an enemy is approaching even if you can't see it yet. Then it seamlessly transitions back to the regular music.
 * The night battle music in Wind Waker was particularly Nightmare Fuel-errific, for example, when fighting those goddamned Seahats in the open sea at night.
 * Ocarina of Time had the Hyrule Field battle theme, and the Dungeon/Nighttime battle theme. Twilight Princess has day, night, and Twilight Beast battle themes, as well as Variable Mixes of the local music themes.
 * Another thing to note is that often times the battle music is less intense until you the first blow is dealt (by the player or the enemy), then the music gets more intense.
 * The Splinter Cell series makes extensive use of situational music, supposing you're less than a perfect sneak. By the time Chaos Theory rolls around, there are three levels of music corresponding to the enemies' awareness of Sam (they know someone is lurking, they have spotted him, they have severely wounded him/boss battle), with clean tempo cuts between each. Otherwise, complete absence of melodic music is the norm.

Adventure Game

 * Hype: The Time Quest has a battle fanfare. The same one for every boss.

First-Person Shooter

 * Besides the Boss Themes, the Metroid Prime series employ Villain Music quite often. Any time you're in a Space Pirate facility, a certain song starts playing, changing to a full-fledged "Space Pirate Theme" when the Pirates appear. Metroid Prime 2: Echoes has a theme for Ing battles and another to possessed Trooper confrontations. And before the 3D games, Metroid II: Return of Samus has different music for the evolved Metroid battles. (also, unrelated to Villain and Boss, regular monsters that are more dangerous get an ominous theme)
 * Deus Ex shifted adeptly between regular music and battle music, with each location having its own.
 * Left 4 Dead uses distinct musical cues to alert players to the presence of the special Infected; as the game is presented as an interactive zombie movie, it's treated as the "score" adapting to the AI Director's sadism.
 * Star Trek Elite Force 2 has this big time. You have the dinking around music, the scary suspenseful music, then the Scare Chord followed by the battle music. Also another Scare Chord for death and an "end the level" diddy.
 * In Borderlands the local dungeon music for each area gradually shifts into a more intense theme when in combat, then shifts back once everyone is dead.

Mecha Game

 * Super Robot Wars does this in a very unique way, as battle themes are mostly dependent on the character attacking, depending on which series they represent. For most characters this is usually their series' opening theme, but certain characters may also use different themes (minor pilots, for example, may use the series' Battle music), while a Special Attack or Finishing Move that has it's own theme in-series will use that.
 * The Original Generation by series' developer Banpresto takes it one step further, where nearly every heroic and villainous character gets his or her own unique battle theme.

MMORPGs

 * Final Fantasy XI is one of the few MMORPGs that change the music when you go into a battle. What's more, the music changes depending on whether or not you're on the overworld, in a dungeon or fighting a boss... and expansion regions have new versions of all of these. There are at least fifteen battle songs in all.
 * Aion is another MMORPG that has different music for when you go into battle, a different one for each sub zone. Some of them are orchestrated peiced, others are metal, but in the large pvp area, the Abyss, there are ten different techno themes that can play any where at any time when you battle.
 * World of Warcraft normally has nothing battle-specific (though some themes play specifically in the boss room) but seems to slowly get into the idea of it. The Trial of the Champion/Crusader dungeons, where you fight bosses one after another, play battle-oriented music, and the Gunship encounter in Icecrown Citadel has theme all of it's own, as do some of the bosses of the Frozen Hall dungeons.
 * Note that there is an addon that lets you use MP 3 s for this purpose.
 * Everquest 2 has dynamic music, where the music changes on how well you do you in a fight and there are several diffrent themes and even a victory/player death music.

Platform Game

 * Sonic Unleashed has a rather catchy and ridiculously upbeat big-band swing theme that plays during fights on the "Werehog" stages.

Real Time Strategy

 * Shows up in a couple of Real Time Strategy games - Homeworld has exactly three (excellent) battle-music tracks that play at certain scripted points in missions.
 * Command and Conquer: Generals uses a heavy metal remix of your faction's music whenever your troops are fighting.
 * C&C3: Tiberium Wars switches over to a faster, more upbeat track if there's shooting going on, even if you order one of your own units to shoot the ground. Presumably it is scripted to go off if any of your units are in the "shooting" state.
 * In Homeworld 2, regular battles have upbeat tracks but boss battles have creepy ones. Keepers and Movers have their own battle tracks, here and here. The boss battle with Makaan goes to an eastern-sounding tune with Sanskrit lyrics (a remix of this plays during the credits as well) while the final battle goes with a really depressing one. Note that these tracks play during space battles.
 * Homeworld avoids it entirely with the entire soundtrack including battle musics being composed of monotone, Middle East-style music. A little sample...
 * Haegemonia Legions of Iron has a lot of different battle tunes. It's worth noting that they are made of distilled awesome.

Role Playing Game

 * Tales of Eternia and Tales of Symphonia had a battle theme for each world. Symphonia, in particular, went nuts with this: it had separate battle themes for Sylvarant, Tethealla, the Renegades, the Desian Grand Cardinals, angels, Summon Spirits,  and Yggdrasil, as well as a separate theme for the battles with party members.
 * Tales of Hearts has thirteen battle themes. Several for different stages of the game, separate subclasses for dealing with normal and boss-type Zerom, and some more for dealing with regular bosses, a couple for The Rival, one for The Dragon, one for each phase of the final boss... The composer for the game is series veteran and master Motoi Sakuraba, so it's only expected that they are all awesome.
 * Symphonia's sequel similarly has a ton of battle themes - one for Sylvarant areas, one for Tethe'alla areas, one for new areas, one for the Coliseum/Ginnungagap, two general boss themes, one for the Vanguard, one for, one for , and one for.
 * Tales of Vesperia gave us four regular battle themes (one for each third of the game and one for the Very Definitely Final Dungeon), one for the coliseum, the major boss theme, the Entelexia battle theme, and a battle theme for various major characters: Zagi,  each have their own battle themes. Yeager is given one as well in the Updated Rerelease.
 * Tales of Xillia ups the ante further with six regular battle themes: depending on whether you chose Jude or Milla as the "main" character at the start of the game, you get a different set of three battle themes (one for each third of the game) and a seventh for the Very Definitely Final Dungeon. Jude's battle themes use electric guitar as their main instrument, while Milla's use the violin.
 * The Earthbound series has different themes depending on what kind of monsters you fight, including the bosses.
 * It's worth noting that Earthbound's sequel, Mother 3, has an absolutely astounding number of different battle themes, not counting remixes (for the purposes of the rhythm-based battle system). Even more impressive, they cover a stunningly wide variety of musical genres, from rock to blues to jazz to Latin to orchestral to techno and back again.
 * Suikoden II has a variant - when the plot takes you to the country where the first game was set, the battle music changes to a remix of the original Suikoden battle theme.
 * In Suikoden V, having certain characters in your active party would change the battle music. Having the conductor would change it to a stirring orchestral piece, and having the rock star would invoke a Ys-style heavy metal remix.
 * Skies of Arcadia had a number of battle themes. The music would even change in boss battles between "normal", "crisis" when the party had low HP, and "triumphant" when the party had high HP and the enemy had low HP. Hearing the switch from one to another when using a particularly meaty special move is very satisfying.
 * Mario & Luigi: Bowser's Inside Story's regular battle music changes depending on whether you're playing as Mario and Luigi or Bowser.
 * Fire Emblem has a Battle Theme for both the player and enemy army, Boss Theme and Big Bad Theme until the third game. From the fourth game on there is also a Villain Theme and a special theme for enemy units that could be recruited was only present in the fourth game. Path of Radiance mixed things up by giving new battle themes for both sides midway through the game and Radiant Dawn added battle themes for each army present in the game.
 * Dark Cloud: most of the battle music early on was the same, but in the later parts of the game the battle music was removed entirely in favour of dungeon-specific music. This was very welcome seeing as the normal battle music sounded like someone throwing marbles at a xylophone.
 * Kingdom Hearts and its sequels also feature separate battle themes for each world. As with the Legend of Zelda example above, it activates when an enemy is nearby even if you can't see it.
 * Freelancer has different background music for Liberty, Bretonia, Rheinland, Kusari, and the Independent, Border, Outer and Edge Worlds. The battle theme for each of these is a faster-paced Variable Mix of the normal BGM.
 * Shin Megami Tensei: Nocturne changes the refrain of the random encounter music every so often to keep things fresh.
 * There's a special case in the Japanese RPG Dual Orb 2, which has one battle theme. ONE. For EVERY BATTLE, from the first all the way to the final battle. And given the skewed chances for a random encounter, you'll be sick of it far before then.
 * The World Ends With You has a soundtrack that it picks from at random for each random encounter. Has the effect of keeping all of the music fresh, since you never get one single tune repeated ad nauseum. ( It also helps that all of the music is awesome in its own right, and is taken from the real world instead of being fabricated for the game, which fit the theme of the game. )
 * Actually, it was all fabricated for the game. It's just THAT good.
 * Every Pokémon game after and starting with Crystal typically have different music than the normal encounter theme when you go up against a legendary Pokemon. Sometimes, a legendary Pokemon that roams around the game world will have a unique encounter theme, and this can very easily overlap with Nightmare Fuel if you aren't expecting it.
 * In Pokémon Gold and Silver there is an additional battle theme for the regular encounters in Kanto. In Pokémon Black and White, there is an additional theme for the Pokemon fought in Victory Road, or just special encounters in other areas.
 * The Baldurs Gate and other Infinity Engine games used Battle Theme Music several times, often having specific music for random encounters vs. plotted ones and so on.
 * Almost every Lucas Arts game with both combat and non-combat sections ever, since the creation of iMUSE.
 * Including, but not limited to, the many Star Wars space simulators, where original Star Wars themes were worked into each other so that the music escalated from one famous tune to another, more upbeat one, as the combat situation evolved.
 * The Final Fantasy series, obviously. The themes reference each other a bit, as you can hear in this here retrospective covering ones from the main series up to number ten.
 * This video might be a slightly better reference, as, though it lacks Final Fantasy VIII's Man With the Machine Gun, it doesn't cut off the ends of the earlier themes, and has the most up-to-date version of Final Fantasy IV's theme.
 * Star Ocean the Last Hope had a standard battle theme used for most worlds with two exceptions. The battle music for Roak is a remix of the first game's battle music, while the battle music for En II is remix of the second game's battle music.
 * And Star Ocean Till the End of Time has a standard battle theme which is essentially a remix of the second game's battle system with some original notes, and have some boss battle themes that are from other tri-Ace games.
 * Wild Arms 1 AlterCodeF does something interesting with random battle music. If you have less than a full party (due to plot-related circumstances), then it plays a remix version of the standard battle music. And if you're in control of Calamity Jane (due to plot-related circumstances), it plays her music as battle music.
 * Whenever something turned aggressive in The Elder Scrolls III: Morrowind, there was an abrupt shift between the background music and the generic battle theme. As an aside, when modders tried to disable audio track shifting to improve game speed, the game threw a fit.
 * Same for Oblivion, to the point where the game gets suddenly much harder if played with the volume low: 'tension music' helps indicate the range of nearby, unalerted enemies and 'battle music' frequently saves you from getting jumped in the countryside.
 * Breath of Fire IV gives you two battle, boss, and victory musics apiece, three for the eastern side of the world, and the same for the west. The eastern side music is your typical RPG high-fantasy epic-adventure fare, but the western side music consists of these badass Chinese-influenced drum-n-bass pieces that will make you wish Capcom had packaged in a soundtrack CD with the game.
 * Mana Khemia features at least three different random battle themes, one for every grade the characters are in, plus several boss battle themes; most of them are incredibly catchy.
 * In Dragon Age, you'll know you're about to fight Darkspawn when this theme starts playing.
 * Phantasy Star III has 4 different Random Encounter themes. The first one plays when you see the enemies appear. Once the battle actually starts, the game plays one of three other themes. Which one is played depends on how well your party was doing. If your party is at a major advantage, or has just surprised the enemy, upbeat, optimistic music plays. If neither side has a major advantage, tense music plays. If you're ambushed or in trouble, the music will reflect this very clearly with a 'You're in trouble now' soundtrack. The music changes between these 3 themes in battle to reflect how well you're doing (or not).
 * MARDEK 's normal combat music carries a more classical feel to it, though still engaging and epic, and feels right for a combat theme. Word of God says that this theme will change with the latter half of the series, though.
 * For a GBA game, Golden Sun has quite a few battle themes. As of Golden Sun: The Lost Age we have the battle themes of Isaac, Felix, Jenna; the first and second boss themes; the battle themes of Saturos, Saturos and Menardi, Fusion Dragon, Doom Dragon, Linked, Colosso, Ship, Karst and Agatio's, the Dragons, and 'finally the "non-adept" battle theme.
 * Beast Signer got 6 different battle teams and the game is not even done yet.
 * In Endless Frontier, each character has a battle theme associated with them, and whenever the player gets into a random encounter, one of those themes were selected at random for that battle. The sequel, however, had so many playable and assist characters that the game only selected battle themes from your active party and their supports... and since certain characters had two battle themes associated with them in that game, you could have a pool of ten battle themes used in random encounters. Out of twenty-one.
 * Outside of boss battles, every battle theme in Harry Potter and the Chamber of Secrets is a more intense remix of the theme for whichever area the battle was taking place in.
 * Persona 3 has the rather catchy "Mass Destruction" as its normal battle theme. Persona 3 FES adds a heavier remix for the Playable Epilogue. Persona 3 Portable adds a new theme, "Wiping All Out", for the female main character.
 * Atelier Rorona and Atelier Totori both feature your standard battle themes with a catch: If it's your first time fighting a strong random encounter enemy, the battle themes in both will switch to a more off-tune, violent and overall chaotic version of the normal battle theme. You'll know it when you hear it, and god help you if you didn't bring enough healing items...
 * The battle themes in Xenoblade Chronicles differ based on whether you or the enemy takes the initiative in the starting the battle. There's a pair of themes used for the majority of the game, a pair that's only played in the  areas, and a theme that's used exclusively for the enemies fought past the Point of No Return on the way to the final boss. Save for a few exceptions, all of the battle themes, be they boss or otherwise, can also be overridden by one of two other themes; one that plays when you change the future, and one that plays when your party is in low spirits.

Simulation Game

 * Free Space generally has very slow, quiet themes for its missions, that almost seamlessly switch to more upbeat battle themes whenever enemies show up using a Variable Mix. All of its soundtracks have three different battle themes, varying in intensity, to use accordingly with how much action is currently taking place.
 * Wing Commander's use of situational music was part of what made Sound Blaster a home name in computer gaming.
 * Special mention must be made to WC2, when you target a capital ship and arm a torpedo. It has a unique tune that's timed to play differently with each stage of a typical torpedo run. Never before (and arguably never since) has sitting and waiting for a target lock been so awesome.
 * In Star Trek Bridge Commander, the music shifts depending on how well you're doing. If you and your allies outnumber and out-match the enemy, an almost fanfare-like, optimistic theme plays. But do poorly, or be totally outmatched (like going up against a Borg Cube alone) and the music turns deadly and pretty much tells you This Is Gonna Suck. It should be noted that Borg Cubes don't exist in the original game, but the "This Is Gonna Suck" theme plays anyway WITHOUT any extra scripting or programing due to the Cube having a higher HP total than your ship.

Survival Horror

 * In the original Alone in The Dark, a Scare Chord plays and the music gets creepier when an enemy appears.
 * In Resident Evil 4, mooks, especially Ganados, have various creepy battle musics depending on the location.

Third-Person Shooter

 * In the Syphon Filter series, each mission's theme has a more intense Variable Mix. Omega Strain, in addition to variations of the local music, has special battle themes for the leaders of each terrorist faction.

Turn Based Strategy

 * As battle is separate from other screens, the Heroes of Might and Magic games naturally have battle music, randomly selected from a handful of tracks.

Visual Novel

 * Not quite a 'battle', per se, but the Phoenix Wright games feature courtroom music that gets more tense as the testimony continues, and finally bursts into a triumphant theme once you've got the suspect cornered.
 * Played with to the point of nearly breaking in the third case of the first game, where the "Cornered" music starts, stalls, starts again, stalls again, and then finally plays in full as the questioning of the key witness stumbles.
 * Sometimes, the prosecution gets the music to play in their favor if they have you cornered. Very noticeable with Klaver Gavin who plays air guitar and has a rocking guitar theme if he feels the tides are in his favor.