Antagonist in Mourning



""It reminds me of the time my dog actually caught a squirrel, after all those years of trying... He looked sad. Like he'd ruined something for himself.""

- Jon Stewart

An antagonist discovers the hero they've opposed for quite a while has apparently met their end, death or otherwise. After all these years, they're gone. It's too good to be true.

Cue a rather bizarre sense of a loss. This may just be the result of the loss of the thing that was a driving motivation in the first place, but occasionally the villain might even seem to genuinely miss him. Luckily, the hero may well turn up alive somewhere else, and the mourning will quickly be dismissed as things return to status quo. Also a common cause/symptom of Foe Yay.

Contrast And There Was Much Rejoicing. Sister trope of Victory Is Boring. When the fandom does this to a hated character's death, it's Alas, Poor Scrappy.

Anime and Manga

 * In Lupin III, Inspector Zenigata's obsessive pursuit of Lupin tends to make him very unsettled whenever Lupin is actually caught, although this is always temporary. Zenigata also openly mourned the loss of Lupin when he was thought killed.
 * Similarly, Lupin is fond enough of Zenigata to mourn Zenigata's apparent death in the Non-Serial Movie The Last Job.
 * In a coincidential meta-example, Goro Naya (the voice of Zenigata) was the one to provide the eulogy at the funeral of Yasuo Yamada (the voice of Lupin).
 * At the beginning of Yu Yu Hakusho, one of the things that convinces the stuck-in-limbo Yuusuke to come back to life is his rival Kuwabara's tearful bellows to 'come back and fight him' at Yuusuke's funeral.
 * Although most likely never taught the philosophical and spiritual side of Martial Arts in her training, Triela of Gunslinger Girl solemnly and sadly returned Pinocchio's treasured key-ring to him after slaying him in single combat, paying her final respects to a fellow warrior.
 * Viral of Tengen Toppa Gurren Lagann felt this for a long time after learning that his rival, Kamina, died.
 * Nagi in Tenchi Muyo!'s Universe continuity does something like this in the final episode after Ryoko's apparent death, though she's also noticeably skeptical as they Never Found the Body.
 * Technically, they were supposed to be on the same side, but since they spent the majority of their mutual appearances trying to take each other out, Alucard's visible distress as Father Anderson dies in the Hellsing manga likely qualifies. Justified in that it seemed he'd been hoping for Anderson to be the one who's finally able to kill him.
 * In the 2003 anime version of Fullmetal Alchemist, Envy throws a full-on temper tantrum, complete with punching a crater into the floor when he finds out that Dante already "killed" Hohenheim of Light. Obviously, he wanted to do it himself.
 * In Legend of Galactic Heroes, most of the top ranking officers in the Imperial Army, not to mention Emperor Reinhard, mourn for Yang Wenli.
 * Yang also mourned for Siegfried Kircheis, saying he felt like he'd lost a friend.
 * In Death Note, Light feels a profound sense of boredom, if not outright loss, when he finally defeats L, and considers L's successor Near as not worthy of taking up the mantle.
 * In Guyver, Aptom actually watches over the friends of his rival Sho for an entire year, to the point of absorbing/eating other Zoanoids so he'd have a reason to return.
 * Recently in One Piece, this trope gets played with in the case of Buggy. After Whitebeard dies, he flees crying (mainly because he's scared witless). His current crew, however, sees his tears as invoking this trope.
 * Played straight in Chapter 0. Shiki, Big Bad of Strong World was once one of Gold Roger's pirate rivals, but hoped We Could Rule Together. He was outraged to learn that the navy had arrested Roger and was planning to execute him in the East Blue. After the Great Pirate Era starts, we go to Shiki's cell in Impel Down where he's flat on his back, angsting over Roger's death and refusal to join him.
 * In Transformers Armada, Megatron seems to be genuinely upset when he finally manages to kill Optimus Prime, and acts a lot more like his old self after Prime gets better.
 * This also happens in the Marvel Comics Transformers series. Megatron becomes increasingly Ax Crazy after the loss of Prime, attacking fellow Decepticons and going on enraged tangents and generally acting like he got swapped with cartoon Galvatron when we weren't looking.
 * After Cell is defeated in Dragonball Z, Vegeta is so distraught at Goku's death, that he vows that he'll never fight again.
 * MW has Michio crying over Garai after he sacrifices himself with the titular gas to the ocean.
 * In Digimon Adventure, Noble Demon Ogremon heartfully mourns Leomon as he's dying, telling Leomon what a good rival he's been.
 * In Episode 93 of Kirby of the Stars, Dedede gets a big surprise when he learns that his latest prank, which involved exploding watermelons, "killed" Kirby, and that everyone in Cappy Town is having a "funeral" for him to remember his time in the village. Dedede and Escargoon become upset and start crying like babies over Kirby's "death". Dedede places a watermelon at Kirby's "grave", and then Kirby pops back out and eats the watermelon, and Dedede becomes overjoyed and hugs Kirby in realization that Kirby was alright after all.
 * Parodied in Tentai Senshi Sunred, when Vamp goes through this after Sunred becomes seriously angry at him and drops their normal relationship in favour of not talking to him. The irony is that their 'normal' relationship is pretty much Sunred being constantly (and openly) annoyed at him anyway, which Vamp cheerfully seems to accept as Sunred just being Sunred.
 * Happens to Kira in Gundam Seed, after he destroyed the Desert Tiger's mobile suit. That's when Cagalli had to comfort him.

Comic Books
"Rorschach: Is that what happens to us? No time for friends? Only our enemies leave roses. Violent lives ending violently."
 * In Superman comics, when Superman returned from his exile in space, Lex Luthor thought, "Strange. I must admit, I'm almost glad. Despite the strife ... regardless of the inconveniences ... A world without Superman can be pretty mundane, indeed." On the other hand, when Superman was killed by Doomsday, Lex's grief was entirely due to seeing himself as The Only One Allowed To Defeat Him.
 * During the "Funeral for a Friend" arc which followed Superman's death, there was a one panel shot of Toyman mourning the death and admiring Superman's kindness to children.
 * Rorschach sees Moloch visit The Comedian's grave at the end of the Watchmen chapter "Absent Friends".

"Batroc: I will miss you, mon ami."
 * Subverted in Captain Atom #50: Wade Eiling seemed genuinely sorrowful at Dr. Megala's death, but it soon turned out that he was just upset that Megala's death would trigger the failsafe that would reveal all the dirty secrets of the Captain Atom Project to the American public.
 * Deadpool actually bit the bucket a couple times or so in his first series, but the case exemplifying this trope was when he got liquefied by the Weapon X brass because he did not agree with their company guidelines (read: killing children). In the next issue, at Deadpool's funeral, his absolute sworn eternal archnemesis of doom, T-Ray, resurrects him with magic. He did it just so he could play Mind Screw with Wade again, but still.
 * Civil War: The Confession is entirely about this. The fact that said antagonist was formerly best friends with the dead hero and never intended him to die just makes his victory all the more heartbreakingly Pyrrhic.
 * In one of Captain America's earlier 'deaths', his Friendly Enemy Batroc the Leaper bids him a tearful farewell.

"Bruce: "They both gave me my life. It seems fitting that they be buried together." Alfred: "And do you mourn them together?" Bruce: "Yes. I do.""
 * In Batman: Going Sane by J.M. DeMatteis, a series of issues of Batman, Batman supposedly dies, and the Joker apparently becomes sane, got cosmetic surgery, and began calling himself Joseph Kerr....
 * Inverted in the novelization of Batman Begins. Bruce built a sepulture for Henri Ducard/Ra's al Ghul in his family cemetery next to Thomas Wayne after the event, and we have this exchange:

"Augustus Caesar: "...What was it like, Lycius? In the days of the Republic? It was chaos, held at bay by a handful of men: Cicero, for example." Lycius the Dwarf: "The lawyer? My father told me about him. He was a great man, wasn't he?" Augustus: "Yes. A fine mind, and an honorable man. The last of the giants." Lycius: "Cicero...whatever happened to him?" Augustus: "I had him killed." (Technically, Mark Anthony did, but perhaps Augustus felt responsible.)"
 * As he lay on his deathbed, Captain Marvel (not that one, the one that belongs to Marvel) had been disowned by his race, the Kree, as a traitor. But the Skrull, whom he had fought for most of his life, sent a representative to present him with a medal reserved solely for Worthy Opponents of the Skrull.
 * Done with historical figures in The Sandman.


 * There is one notable example from The Mighty Thor. For a while, Thor had a hero known as Thunderstrike take his place. Thunderstrike eventually died and Thor was brought back. There was a scene in which the villain Absorbing Man visited his grave in order to pay his respects. Thor witnessed this and, thinking the Absorbing Man had come to defile the grave, began to fight him. The villain was offended by the thought. He angrily pointed out that he had come to mourn someone whom he considered to be a friend despite all of the fights the two had been in and even went so far as to point out that Thunderstrike was more likeable than Thor. It was probably the only instance where Thor apologized to an enemy.

Film

 * A major plot point in Megamind. Megamind even misses the "good vs. evil" battles so much that he creates his own hero...who then becomes a villain, MUCH worse than himself, that Megamind must defeat, becoming a hero in the process.
 * Played With: while he eventually becomes depressed after Metro Man's death, the thing that really makes Megamind cross the Despair Event Horizon (temporarily) is the discovery that Metro Man.
 * Given a nod in Kill Bill, when Bud and Elle think The Bride is dead. Bud asks Elle, who considered The Bride a personal rival/nemesis, which R she feels: Relief, or Regret.
 * More importantly, Beatrix weeps in the bathroom after she kills Bill.
 * Bill the Butcher in the movie Gangs of New York commemorated the death of his Worthy Opponent "Priest" Vallon every year with a public celebration. At one point, he laments that, of all the people he'd killed, Vallon was the only one worth remembering.
 * In Grumpy Old Men, the eponymous characters, John and Max, have been bitter antagonists for years. During the course of their biggest fight yet, John suffers a heart attack and nearly dies. A visibly shaken Max goes to see him in the hospital, and when the nurse asks if he's a relative, he replies, "He's my best friend."
 * Inigo Montoya from The Princess Bride has an interesting variation: while Inigo certainly doesn't mourn Rugen, he finds himself somewhat at a loss without his lifelong quest for revenge. Fortunately, Wesley has an ideal solution: "Have you ever considered piracy? You would make an excellent Dread Pirate Roberts." Interesting is that this one is a Protagonist In Mourning.
 * In Kagemusha, when the death of Shingen Takeda is finally revealed, one of his rivals sings a song of mourning.
 * Lampshaded by M. Bison in Street Fighter after learning that Guile was seemingly killed in some random prison escape, claiming that he deserved the honor of going out with a broken spine at Bison's hands.
 * Nobody dies, but in the movie Spider-Man 2, Spidey hangs up (actually, throws out) the spandex. Jameson is just beginning to admit that the world is a darker place without him when the costume he had bought and pinned to his wall was swiftly abducted, changing his opinion mid-sentence.
 * In X Men the Last Stand, Magneto sincerely grieves over Xavier's death and even cuts off his Dragon Pyro's irreverent talk about the deceased abruptly. As in most versions of X-Men, Xavier and Magneto were very close friends who eventually found themselves on separate sides due to their ideological differences.
 * Heathers has J.D. mourning over Veronica after she faked her suicide.

Literature

 * Happens to Alanna in Tamora Pierce's Tortall Universe the first time she kills Roger. (He got better, so she had to kill him again, this time for realsies).
 * A temporary example in the first Artemis Fowl book when Holly mourns Artemis' "death".
 * Commander Root also displays a mild version of this when Mulch Diggums fakes his death.
 * In return, Mulch is horrified when Commander Root really does die at the hand of Opal Koboi.
 * In The Cardinal of the Kremlin by Tom Clancy, a Soviet general shows up at the eponymous character's funeral, despite the Cardinal being a traitor and American agent - but he was a national hero after all. While the general seems to accept the explanation and stays out of respect, he shows up without knowing the reason, only having been asked by the President of the United States, and as a person connected to the embassy, it would not do for him to decline.
 * Several times in Romance of the Three Kingdoms, Cao Cao is respectful of the soldiers he captures and cannot persuade to join his army, forcing him to execute them. He demands their loyalty be recognized and has them buried with full honors.
 * In The Book of Dreams, the last book of Jack Vance's The Demon Princes series, the last line is Gersten contemplating the fact that he has destroyed all five of the Princes, completing the vengeance he was raised from boyhood to achieve: "I have been deserted by my enemies. Treesong is dead. The affair is over. I am done."
 * Stephen Vincent Benet's "Elegy for an Enemy".
 * Exit Music, the last Inspector Rebus novel (for now...?) by Ian Rankin. Rebus's arch-nemesis Big Ger Cafferty, the man who has been behind - or at least involved with - practically every criminal plot Rebus has ever investigated, suffers a heart attack at the end of the book. Rebus leaps on him, starts CPR, shouts for medical assistance, and quite disturbingly shouts "Don't die...don't let him die!!"
 * Frankenstein: when the creature realizes that Victor has died, he calls Victor the "select specimen of all that is worthy of love and admiration", despite having pursued the man to his end.

Live Action TV
"Stephen: I'm conflicted here. Sure, I'm happy he's gone, [tearing up] but I have spent so much time hating him...that I think I love him."
 * The Dukes of Hazzard did an episode where Roscoe thought that Bo and Luke had drowned. Roscoe, who spent years as an enemy of the Duke family, was genuinely mourning them as much as their friends and family. The narrator had a line that summed up this trope, "Sometimes, losing an enemy can be like losing a friend."
 * Roscoe isn't really a bad guy though, he's a genuinely good lawman who's been duped and controlled by Boss Hogg.
 * Stephen Colbert on Fidel Castro's retirement:

"Ben Linus: [Delivering a eulogy] John Locke was a believer, he was a man of faith. He was a much better man than I will ever be, and I'm very sorry I murdered him."
 * Wiseguy. Music industry Big Bad Winston Newquay is genuinely upset over the death of his long-time rival Isaac Twine, though that doesn't stop Newquay carrying out his side of their bet to dance on the grave of the one who dies first.
 * In Star Trek: Deep Space Nine, Sisko has a deeply antagonistic relationship with Eddington, who betrayed the Federation. Sisko is utterly single-minded when hunting Eddington down. When Eddington and Sisko are in battle together, though, the wounded Eddington has to turn a gun on Sisko to convince him to leave him to die in battle. Sisko later acknowledges that Eddington the most loyal man he knew.
 * A version where the protagonist mourns the antagonist is in Doctor Who, when the Doctor is shaken by and mourns the (apparently permanent) death of the Master. Of course, at that point, their relationship pretty much defines Foe Yay.
 * The classic series had the Master mention that the universe would be empty without the Doctor. Three and the Master as played by Delgado were pretty pally.
 * Heroic version on The Wire: When Stringer Bell is murdered, McNulty is distraught, as he had finally acquired the evidence to bring him in for good.
 * Not just that: he'd gotten the information the very afternoon that Stringer is killed.
 * The Trickster would probably mourn if the TV version of The Flash were killed, as evidenced by his scolding his female assistant when she even suggests killing the unconscious speedster. He even threatens her for trying to unmask the Flash, as his antagonistic fixation depends on the hero being some kind of god.
 * Both the beginnings of a Heel Face Turn and a Crowning Moment of Funny in the sixth season of Lost:

"Frank Lapidus: (Burying the body) Weirdest damn funeral I've ever been to."
 * Bonus funny points because none of the other characters were aware of that last bit beforehand. Cue some reactions of "wait, what?!?"


 * Locke's primary antagonist Jack didn't take his death very well either. In death Locke earned more respect from Jack and Ben than he ever did when he was alive.
 * In a period of the show before their relationship became friendlier, Police Captain Leland Stottlemeyer became upset in an episode of Monk when he thought the titular character was dead, despite not liking him very much. Humorously, he says "I loved that man", then finds out he's still alive, then says "I hate that man!"
 * In the new 2010 edition of Romance of the Three Kingdoms, upon Zhuge Liang's death, Sima Yi is portrayed as saying the following words (translated from the original): "Now that you are gone, who else can know my mind as well as you did? Will I not be lonely?"
 * A variation on the Protagonist in Mourning angle occurs in Sanctuary. When Tesla is, Helen is saddened by the apparent loss of all of The Five via death, de-powering, or just leaving her. This, even though non-vampire Tesla is a MUCH easier "foe" to deal with.

Newspaper Comics

 * Thinking that Krazy Kat has drowned, Ignatz weeps into a handkerchief and bemoans his cruelty... until Krazy shows up again, and Igntatz beans him with a brick without missing a beat.

Religion and Mythology

 * Older Than Feudalism: In The Bible, King David mourns for both Saul and Absalom, the former of whom tried to kill him before he became king and the latter who overthrew and exiled him. They were family, though (the former his father-in-law, the latter his son).

Theatre

 * Done in the play Amadeus where Salieri is, for many years, Mozart's Unknown Rival and seeming friend, but works covertly to ruin his life. As Mozart continues to produce great works while losing everything, Salieri ironically ends up becoming the only person who realizes the full extent of Mozart's greatness and thus ultimately mourns him more than anyone else.
 * In Julius Caesar, after Brutus dies, Antony calls him "the noblest Roman of them all", and says that the others conspired against Caesar out of jealousy, but Brutus did it because he thought it was right. He and Octavian agree to give him a respectful burial.
 * While most productions do not portray him as a full-on antagonist, in Jesus Christ Superstar, Judas has a complete emotional breakdown after helping Jesus' arrest and execution, and commits suicide.

Video Games

 * In Sonic Adventure 2, Dr. Robotnik utters a respectful farewell to Sonic after he thinks he's killed him.
 * Shadow watches Sonic's "death", commenting, "I guess he was just a regular hedgehog after all..." in a slightly disappointed tone.
 * In Tales of Vesperia, after helping to orchestrate a long chain of events that involves the death of Don Whitehorse, Yeager proves himself to be a Jerk with a Heart of Gold when he shows up in Dahngrest with a bouquet of flowers, indicating that while what he did was business, he personally regrets the loss very much and needs time to mourn before returning to his job. At least, that's what he says to the party.
 * On the online game Dragon Fable, Warlic is killed by his apprentice, Natherya. The people of Falconreach hold a funeral in front of a statue of him. Then, his greatest enemy Xan shows up, obviously angry over his death. However, Xan says that HE wanted to be the one to kill him, and is given the idea to bring him back to life just to kill him again. Do the math and guess how that turns out.
 * Happens in World of Warcraft when you kill Illidan. His last words to Maiev are "You have won...Maiev...But the huntress...is nothing...without the hunted...You...are nothing...without...me..." She agrees.
 * Some of a light-side player's dialogue after killing Malak in Knights of the Old Republic.
 * In Mafia: The City of Lost Heaven, Don Salieri is completely depressed after thinking that the main character had succeeded in killing his best friend and adviser, who had betrayed him after his wife and child were kidnapped (this follows a literary tradition of mobsters going to each other's funerals and providing for each other's families, even if they themselves had been responsible for the death). In truth, Tom (the main character) spared him after saving his family and setting right what his betrayal screwed up. Ironically, that didn't stop him from finding out he was still alive, having him killed for real, and putting out a hit on Tom for having spared him.
 * In Halo, even though they are now more allies than enemies, the Arbiter consistently says "Were it so easy" whenever someone makes a jab at killing Master Chief, or even on the rare occasion where he is killed by a Covenant or Flood enemy. He looks specially sad at the end of Halo 3
 * In Sengoku Basara: Samurai Heroes, Ieyasu and Mitsunari will mourn each other's deaths and cry openly (though for different reasons) in their red paths.
 * One of the endings of Heavy Rain, "Ethan's Grave", show Scott Shelby, aka the Origami Killer, hiding behind a tree, looking sad at the titular ending.
 * Roy Earle in LA Noire appears, giving a eulogy in the end at Cole Phelps' funeral, but he's faking it, making it a subversion.
 * Wings portrays the Allied forces as having a "bittersweet" reaction to the death of Manfred von Richtoffen. Truth in Television, as this really is how they reacted; see also the real-life section.
 * Batman: Arkham City presents a possible inversion, in which Batman is the one to carry Joker's dead body out of the cinema at the end, before the solemn silence of his gang (Harley included) and the police's amazement.

Web Comics

 * Gilgamesh Wulfenbach in Girl Genius spends several months in deep mourning when Agatha fakes her own death to escape capture by his father. While Gil never really saw himself as her enemy, his father, Baron Klaus Wulfenbach, has thought of her as a threat since he first realized that she was the missing Heterodyne heir, and the Baron only becomes more convinced when he learns that she can order the Other's minions and open portals in space-time. As Gil remains loyal to his father, and is also worried by the evidence that she may be the Other, he plans to capture her and verify that she isn't evil reincarnated before wooing her.
 * Wooing her "Most Vigorously"!
 * Parodied in The Non-Adventures of Wonderella: "The DEATH of Wonderella", where Arch Enemy Hitlerella tries to take up Wonderella's mantle.
 * Nerf Now, "She was just level one", Team Fortress 2 arc, ends with Red Team engie lured on turrets by a spy and dying on the hands of Blue Team engie. And when it seems to be over, there's "Revengineer 2", where Blue Engineer visits his grave and meets a weeping female Red Engineer there...
 * Amazing Super Powers parodied it in the end of Slaughterbot arc.

Web Original

 * Neopets has an (Anti) Heroic example: after the death of longtime villain Hubrid Nox in "The Faeries' Ruin", the Advent Calendar featured an animation of Magax, visiting Nox's grave and holding a present he'd presumably bought before Nox's death.

Western Animation
"Joker: Well, that was fun. Who's for Chinese?"
 * Inverted in Sonic the Hedgehog when, in the series finale, Sonic says, "No more Robotnik. Too bad." Sally looks confused until he adds, "Without a villain, what's a hero for?"
 * Pictured above: in one episode of Batman the Animated Series, no-name goon Sid "The Squid" accidentally convinced many people, himself included, that he had killed Batman. The Joker was skeptical, but after holding up a jewelry store and just waiting there several hours to see if Batman would show up, Joker's skepticism and glee gradually vanished. In his usual bizarre way, Joker mourned the loss of his favorite adversary by holding a symbolic funeral for Batman inside the Joker's "birthplace", the Ace Chemical Plant, locking Sid in a coffin, and dropping it into a big vat of acid. Batman, having survived the unintended explosion in the beginning of the episode, turned out to be watching from the shadows the whole time, waiting for his apparent demise to make a particularly troublesome crime boss careless.
 * In typical Joker fashion, he bounces back afterward with a smile:

"Bugs Bunny: Well, what did you expect in an opera? A happy ending?"
 * When Superman was thought killed by the Toyman on Justice League, Lex Luthor appeared at his funeral. Despite the disgust of Lois, Luthor admitted to genuinely missing him.
 * And then in the DVD movie Superman: Doomsday, Luthor gets positively homoerotic with Superman's clone.
 * The plot of roughly 75% of Invader Zim fanfiction.
 * And one unproduced episode. In it, Dib gave up to learn "real science" and takes a fifteen minute retirement. By the end, they're both depressed, and become "friends" again, or something like that.
 * But somewhat pointedly Averted Trope in "Bad, Bad Rubber Piggy". Zim manages to (temporarily) kill Dib (as a little kid!) and his response is...to quietly take a sip of his drink before merrily going on his way.
 * After Optimus Prime died in Transformers Armada, Megatron lost most of his motivation, and became bored and depressed at the loss of his rival, and disappointed that he hadn't been able to deliver the death blow personally. After Prime's inevitable yet miraculous rebirth, Megatron swiftly returned to normal.
 * And it was a slightly less drastic situation in the Marvel comic: when Optimus died, Megatron went so Ax Crazy it was like Galvatron came early. In the end, Shockwave sends the Predacons to kill him so that he won't further endanger the 'cons. Unfortunately, madness also doubles as Unstoppable Rage nicely.
 * Dr. Drakken gives Kim Possible a brief eulogy when he thinks she's been shot by a laser cannon in "Graduation."
 * In the classic animated short "What's Opera, Doc?", a parody of Richard Wagner's works, Elmer Fudd as Siegfried hunts down Bugs Bunny in retaliation for the latter's disguising himself as Brunhilde. When he finally succeeds in his attempts to "kill da wabbit", he regrets it and tearfully carries Bugs away, cradled in his arms. Bugs revives for a moment to address the audience:

"The Joker: "I can't believe it. He's...he's actually gone. Let's take a moment to reflect on the passing of a man who was more than just another do-gooder in tights! He was the best archnemesis a sociopath could ask for! Okay! Lets do it again!""
 * Danny Phantom: Though he doesn't outright say it, Vlad Masters in a Bad Future blatantly admits his terrible actions resulted in the loss of those he was close to, mourning them for ten years strong--including Jack.
 * Re Boot: After Bob is gone, Hack and Slash realize that there is no one to stop them from finishing their evil acts anymore. This distresses them intensely.
 * It also helps to remember Hack and Slash are a bit of a relic from when Re Boot was a kid's show. When the series got Darker and Edgier, they didn't.
 * In The Fairly Odd Parents "Wishology" trilogy, Vicky actually breaks down sobbing after Timmy's Heroic Sacrifice.
 * In the Phineas and Ferb episode "Come Home Perry", Perry the Platypus was relocated to a new family and a new villain, and like everyone else who knew him, Doofenshmirtz was feeling a bit sad with the loss.
 * An inversion has Perry severly depressed and feeling betrayed after Doofenshmirtz gets a new nemesis and doesn't need him anymore.
 * Doofenshmirtz felt sad the one time he believed he had destroyed Perry.
 * Tom and Jerry Tales has the titular cat crying for the titular mouse, thinking he is killed by being crushed by a pillar. Afterwards, Tom gets haunted by Jerry's "ghost", not knowing that the mouse is alive and that he and his bat-lookalike are trying to scare him.
 * In the Batman the Brave And The Bold episode "Requiem For A Scarlet Speedster", The Flash (Barry Allen) has died, and his old rogues' gallery fondly remember fighting him, and say that Jay Garrick and Wally West "just aren't the same". They don't miss him, of course. Oh no.
 * In the episode "Emperor Joker", when The Joker obtains God-like powers, he finally defeats Batman. Though seemingly saddened by the loss of his adversary, it's immediately subverted when he laughs it off and resurrects him to do it again and again.


 * Peter Pan has Captain Hook doing this when he believes the titular character died from the exploding gift he gave him.
 * In a Christmas Episode of Peter Pan and The Pirates, Captain Hook looked at a future where Pan initially felt like he had no reason NOT to grow up once Hook died. However, Pan eventually forgot Hook, and even finding the hook that replaced the pirate's eaten hand wouldn't trigger memories.
 * Averted hard in the book. Hook dies and everyone goes home, but when Peter Pan returns to Wendy he has no memory of Hook... and indicates he has a long string of villains that he forgets after they die. Creepy.
 * In a non-death example, Bart gets Principal Skinner fired and soon realizes that he misses him as an enemy (the new principal is Ned Flanders, who is too nice to curb any kind of misbehavior). Lisa mentions the trope, explaining that Moriarty needs his Sherlock.

Real Life

 * Uesugi Kenshin reportedly cried at the death of his greatest opponent, Takeda Shingen, with whom he had previously fought a lengthy series of battles.
 * Fidel Castro felt this way about President Kennedy; when asked about his assassination, Castro said, "What I felt when I heard that news is someone who has an adversary, someone who respects his adversary and all of a sudden, someone else kills his adversary. A boxer in the ring for example, and the adversary is shot to death in the middle of the boxing match."
 * Manfred von Richthofen was regarded with the greatest respect by most Allied airmen. When he was eventually shot down and killed in 1918, his aircraft crashed behind allied lines in a sector controlled by the Australian Imperial Force, and he was given a funeral with full military honours by No. 3 Squadron, Australian Flying Corps.
 * Julius Caesar wept at the death of his friend turned rival Pompey the Great, after being presented with his severed head and hand by the Egyptians after Pompey tried to seek sanctuary with them. Some of this, of course, might have been for good P.R., but he might have also genuinely believed that Pompey deserved a far more dignified end.
 * Speaking of Rome, Plutarch writes that Octavian wept when a member of Mark Antony's bodyguard brought Antony's sword to him. It was almost certainly not because of any lasting affection for him, but by that time, they had been fighting on and off for fourteen years. Not to mention, Octavian had crushed every single one of his enemies at last. The feeling of so many years of conflict finally being brought to a close probably made him pretty emotional.
 * The last chapter ("666") of Hunter S. Thompson's Better Than Sex is a meditation on the death of Richard Nixon. He starts by saying that it was Nixon (or rather, his dislike of Nixon) that got him into politics, and "now that he's gone, I feel lonely"...and then ultimately subverts the trope by eviscerating the late president, writing a vitriolic screed that finishes by saying that Nixon "killed the heart of the American dream."
 * Erwin Rommel received a moving tribute from Churchill upon his death; it was still the middle of WWII at the time.
 * Formula One champions Alain Prost and Ayrton Senna were bitter rivals throughout their careers, even crashing into each other at times to screw each other over. Prost even had a clause in one contract that Senna could not be his teammate, the rivalry was so strong. When Prost retired the second time, they tried to repair their relationship, but sadly Senna died a few months later during the Blackest Weekend. Prost, as it turns out, was one of his pallbearers.
 * After the death of Pitt the Younger, his great political rival Charles James Fox said "It feels as if something is missing in the world."
 * Frederick the Great upon the death of Maria Theresa: "I have shed some very sincere tears at her death. She has done honor to her sex and to the throne. I have made war upon her, but I have never been her enemy."
 * When 17th century Dutch admiral Michiel de Ruyter died a week after being injured during a navy battle with the French, the French king Louis XIV fired canons as a salut when the ship carrying the body of Michiel de Ruyter sailed by.
 * After the Battle of Trafalgar, the British respected the Spanish admiral Cosme de Churruca so much that, having captured his ship, they placed a brass plaque on the door of the cabin that had been his, and all who entered it were required to remove their hats in salute to a very Worthy Foe.
 * Pierre Trudeau's funeral provided a twist on the trope: not because old rivals and political opponents paid him tribute and mourned the passing of one of the most charismatic leaders the country has ever had, but because it was an example of Antagonists in Mourning for someone else. The funeral was attended by both former US president Jimmy Carter and long-time American enemy Fidel Castro, who sat beside one another and were both Honorary Pallbearers.
 * Political differences eventually cropped up among the leaders of the movement that became the Meiji Restoration in 19th-century Japan, but that didn't always make things totally bitter. Yamagata Aritomo is notably said to have wept over the severed head of Saigo Takamori, his former comrade who'd led the only rebellion against his regime worth mentioning.
 * Of course, this was very traditional. He may still have actually meant it, though. Especially since rebelling apparently wasn't really Saigo's idea. The conscript army that defeated Saigo's samurai was Yamagata's baby. He was so proud.
 * Actually, no, they never found Saigo's head, though they looked for it.
 * Carlton Fisk broke down in tears when he found out Thurman Munson was killed in a plane crash.
 * From the book Blind Man's Bluff, when an American and Soviet submarine had a severe collision in the ocean, and both believed the other had died, the sailors on both submarines felt genuine regret at the death of fellow sailors, even though they were opponents.
 * When one of the most famous historical figures of Argentina, Juan Domingo Perón, died in 1974, the most touching words of mourning came form his political antagonist, Ricardo Balbín: "This old adversary farewells a friend".
 * When the incredibly Badass English knight William Marshal died in 1219, French king Philip Augustus, who'd been making trouble for England for decades, virtually went into shock. One historian described him aimlessly wandering through his palace, asking everyone he met, "Have you heard that the Marshal is dead?" Even in a foreign court, no one needed to ask which marshal he meant -- William was that famous. Philip later stated William was the most loyal man the king -- the enemy king -- had ever known.