Sad Battle Music

Scenes of the carnage of war, an intense battle sequence, often accompanied by the deaths of some characters, or even war in general, often are accompanied by melancholy music. When feelings of hopelessness begin to take over, you can expect the music and mood to reflect that.

Compare: Playing the Heart Strings, where sound effects are muted for music; One-Woman Wail, where you hear a wailing singing voice; Lonely Piano Piece, where one character or very few characters realize that they're on their own; Ethereal Choir, where a distant choir harmonizes with the scene. All of these can overlap with this trope when they accompany the right kind of scene.

Anime

 * In Dragonball Z episode 25, Krillin and Gohan fight Nappa to a sad fighting theme. Averted in the Western dub, where it is replaced with a more action-y theme.
 * Code Geass has this during.

Film

 * In Braveheart, during the Battle of Falkirk, sad music begins to play as the Scottish nobles William Wallace trusted to help them flee the field instead, and the King of England, Edward Longshanks, orders his archers to fire on the infantry fighting in the front. The music becomes more tragic and dramatic as Wallace attempts to chase after Longshanks, and finds out that yet another Scottish noble he trusted betrayed him, causing him to suffer a Heroic BSOD after witnessing this Despair Event Horizon.
 * Harry Potter and The Deathly Hallows Part 2 has the track "Courtyard Apocalypse", accompanied by watching the Death Eaters and the Order of the Phoenix fight to the bitter end.
 * Star Wars Episode III: Revenge of the Sith gives us "Anakin's Betrayal", which plays during the march on the Jedi Temple, courtesy of Order 66.
 * In the movie of Lord of the Rings: The Return of the King, Pippin sings a song for Denethor. It's a sad melody. At the same time, Faramir and his battalion charge Osgiliath, and it doesn't go well.
 * The slow woodwind solo during the combat at Agincourt in Kenneth Branagh's film of Henry V. Some of the combat sequences are also done in slow motion.
 * Several battles in We Were Soldiers are set to a slow Scottish dirge, Sgt. Mackenzie.

Video Games

 * Final Fantasy VII, in the battle against JENOVA Life. The music that plays is Aeris' Theme, because
 * In Crisis Core Final Fantasy VII, "The Price of Freedom" could be considered this, due to the nature of the event you're fighting to it.
 * Final Fantasy IX: Beatrix's fight theme.
 * Final Fantasy X: When the player is approaching Zanarkand. the music that plays is "Someday the Dream Will End". This even carries over into the Fight Woosh and the actual battle.
 * Lulu's Theme plays when you fight Yojimbo.
 * Likewise, Final Fantasy XIII has the sad background theme replacing the default battle music in all encounters (except the boss) in.
 * Fragile Dreams Farewell Ruinsofthe Moon: It's not an exaggeration to say that Fragile Dreams' final boss music would not sound out of place on The Fountain's soundtrack.
 * Kingdom Hearts:
 * Kingdom Hearts II Final Mix+, during Sora's battle with Roxas. The song that plays is a melancholy remix of Roxas' theme (which was sad to begin with), and it is called "The Other Promise".
 * In Kingdom Hearts Coded,  Similarly, the battles with  are accompanied by his rather somber leitmotif.
 * Kingdom Hearts 358 Days Over 2:
 * In mission 17 of Ace Combat 5 The Unsung War, after, the previous aggressive music abruptly stops and for a minute or so, there is no music at all. Then, just as new waves of enemies arrive, a Simple Score of Sadness picks up and plays until the end of the mission. It's made even worse by your remaining wingmen sobbing quietly on the radio.
 * Tales of Vesperia: A slow melancholic rendition of the game's theme song, Ring a Bell, plays during Yuri's battle with
 * The third installment of the Xenosaga trilogy has the battle between KOS-MOS and T-ELOS. While their previous battles were accompanied by intense music, their final confrontation has the melancholic "Hepatica" playing.
 * Metroid Prime 3: Corruption has sad but intense music during the battle against.
 * Mother 3 does this during.
 * Unlike the others that preceded it, the Final Boss in Shadow of the Colossus has a single, sad musical score that does not change while the battle progresses. It's oddly fitting, considering that, and there's nowhere else to go but to defeat the boss and finish the game.
 * In Mitsumete Knight, there's "Sorrowful Blade", the battle theme played when fighting
 * "Prisoners of Fate" in Chrono Cross plays during the climax of the game's Wham Episode, when it's revealed that . It culminates in the fight against the infamous, who was bound to the Dead Sea by fate.
 * The Final Boss music in Mario and Luigi: Partners in Time.
 * All over the place in Mass Effect 3, but especially during the fall of Earth and
 * Sad But True from Resident Evil 5, battle against.
 * The theme of the Final Battle in Dark Souls against is one of the saddest tracks in the game.
 * The theme of the Final Battle in Dark Souls against is one of the saddest tracks in the game.

Western Animation

 * Avatar: The Last Airbender: The music that plays during the during Sozin's Comet. Fittingly, the music is called "The Last Agni Kai".