As a Death Trope, ALL Spoilers will be unmarked ahead. Beware.
Killing the Ones You Love in Anime and Manga.
- In Amakusa 1637, two events shattered Naozumi Yatsuka's view of the world. One was the phenomenon that got him and his friends Trapped in the Past. The other was killing the first person in said past who understood him, his young and handsome slave Shirou. Yes, that Shirou
. - Raziel from Angel Sanctuary forces himself to shoot his beloved superior Zaphikel when the latter transforms into a ghoul.
- The climax of Assassination Classroom results in this trope. No one in 3-E wants to kill Koro-sensei after the year they've spent together, but know it's either them or the approaching Kill Sat that is going to do the job.
- In the end of Attack on Titan, despite resisting it all throughout the battle with him, Mikasa becomes the only one who can kill Eren and in the series' penultimate chapter she does exactly that, decapitating the man she loves before he can unleash any more carnage. In fact, that chapter has its primary conflict seem to be her working up the courage to go through with it.
- Baldr Force EXE Resolution: Tohru has to kill Ren to keep her from destroying everything in the Wired.
- This is the entire point of the Sacrifice required to become a demon from Berserk, as first revealed in the Guardians of Desire arc. By consigning that which you most love to be eaten by demons, the would-be Apostle (or Godhand) cuts himself or herself off from humanity and opens himself or herself to evil. Unlike most of the examples on this page, this act is presented as a monstrous betrayal of everything the person holds dear and a crossing of the Moral Event Horizon, both because of the Cruel And Unusual Deaths often suffered by those who get the Brand put on them and due to the added little detail that anyone sacrificed in the creation of a demon gets his or her soul condemned to Hell for all eternity.
- Bleach: Rukia Kuchiki was forced to kill her mentor and first love, Kaien Shiba, when he became possessed by a Hollow.
- Blood+: Due to Psycho Serum Delta 67, the heroine Saya's adoptive father George Miyagusuku starts to turn into a mindless bloodthirsty monster and she must reluctantly kill him before the drug takes effect.
- In the Claymore universe, this sort of thing happens all the time due to the whole I Cannot Self-Terminate thing. The first instance occurred in the very first volume when Clare was called upon to Mercy Kill her girlhood friend Elena.
- Code Geass:
- Lelouch (as Zero) is forced to shoot Euphemia after he accidentally Geasses her into killing all the Japanese, sending her on a rampage. Just as he does it, he mentally bids her farewell, and even thinks to himself that she was his first love. He's later shown angsting over it.
- Then there's the finale, where Suzaku, disguised as Zero, stabs Lelouch in a Thanatos Gambit. He's shown crying while doing it. It's also especially tragic because everybody except Lelouch thinks Suzaku is dead and since he was an accomplice in the Zero-Approval Gambit, he can't go public or he'll ruin Lelouch's plans. Also, he can't take the easy way out because his "live" Geass forces him to do exactly that.
- In Corsair, this is a major issue for Canale. His murder of Sesaam, his lover at the time, is the biggest instance but he also feels responsible for his mother's suicide and the general death and destruction that follow him wherever he goes.
- Realising that he has to do this to his Love Interest, Yin because her Superpowered Evil Side will destroy the world if he doesn't causes Hei from Darker than Black to BSOD big time, leading to him becoming the drunken Jerkass we know from the second season.
- Demon Slayer: Kimetsu no Yaiba:
- The crux of Sanemi's tragic backstory exclusive only to him; his mother Shizu was the victim of being turned into a demon during her lone hours in the mountainside, by becoming a mindless demon she came back down to prey on her own children, killing five of them, leaving only two alive as Sanemi jumped to stop his mother and save his little brother Genya; Sanemi tried to hold onto the hope his now demonic mother had any piece of human reason left as he shielded himself of her charges, but his instincts took over and he ended up heavily wounding his mother, with the sunrise effects finishing her off.
- Yoriichi Tsugikuni loved his older twin brother Michikatsu very much, it took him well over 60 years to steel his heart in order to seek Michikatsu, now the powerful demon Kokushibo, to battle him to the death; Yoriichi was fully intended to kill Kokushibo before he died of old age, he must have felt his life wasn't long in this world anymore so he could at least try to atone for his brother's betrayal of the demon slayer corps and save him the shame of living as a terrible human eater and murderer. However, Yoriichi died mid-battle despite having the complete upper hand against Kokushibo, his powerful and gifted human body just couldn't defeat aging, allowing Kokushibo to live for a few more centuries.
- Ga-Rei -Zero-: Yomi. It's even the anime's tag line!
- Ginga Densetsu Weed: The Big Bad Hougen shows remorse when killing his brother Genba, who has his brain damaged beyond repair. When asked by his minions why he would kill his own brother, Hougen replies that he was fulfilling a promise that both Great Danes made together: If one brother was to die, then the other brother would be the one to kill him.
- In Gintama it happened in the backstory of its protagonist Sakata Gintoki. As part of a Sadistic Choice, he had to kill his mentor and father figure in order to spare his fellow students' lives
- In Gundam Build Divers Re:RISE, Hiroto was forced to delete Eve at her request when she could no longer control GBN's bugs she has absorbed within herself. Being forced to kill Eve traumatizes Hiroto mentally and emotionally, and it leads him to conclude that he's a fundamentally awful person, undeserving of praise, of True Companions, or ever being a hero.
- Knight Hunters loves this trope. Loves it. Aya has to kill two of his mentors; Ken has to kill his best friend, girlfriend, surrogate mother, and old friend's brother; and Youji gets to kill three girlfriends.
- Kyo Kara Maoh! likes to flirt with this trope. Particularly Conrad and Yozak — they've been best friends for decades, are probably more comfortable with one another than with anyone else in the world, are the only survivors of their Half-Human Hybrid battalion. But in the second episode in which they appear together, Conrad threatens to kill Yozak if he messes with Yuuri again. This scene is so much freakier when you see it again after learning all the background between the characters.
- Conrad also throws Yozak off a cliff during his Face–Heel Turn, right after Yozak attacked him while giving a declaration that was basically, 'you're my best friend and my captain and if this is how it's going to be I'll kill you myself.'
- And in the weird guest episode with the mountain of betrayal miasma, where everyone except Yuuri became convinced that everyone else had been compromised by the mist of betrayal and become their enemy. Yozak and Conrad had rather a good duel in the snow. Even more impressive in that episode was when Wolfram became convinced that Yuuri had gone crazy was going to kill him and didn't invoke this trope, just curled up and waited. Power of Love.
- When Conrad and Yuuri met in the coliseum it looked like this was going to happen, too, and about ten episodes later it very nearly did.
- In My-HiME, Natsuki takes it upon herself to end her best (and for a long time, only) friend Shizuru's rampage, knowing that both of them will die in the process.
- Naruto:
- Sakura has decided to kill Sasuke with her own hands, to save their land and spare him from falling even lower than he already has. Subverted, as when push comes to shove, she can't bring herself to do it and is nearly killed herself.
- In the backstory, Itachi did this when he slaughtered the Uchiha Clan, including his girlfriend Izumi and his own parents whom he killed last, to pre-empt a coup. A flashback shows him about to cut down his parents who aren't even trying to fight back. Just to twist the knife further, they spend their final moments assuring Itachi that they still love him and respect his decision and ask him to look after Sasuke. Itachi is crying the entire time. Speaking of the Uchihas, the Mangekyo Sharingan is unlocked by the death of a loved one (Kakashi's turned out to be a Suicide by Cop, so it doesn't need to be deliberate).
- Kakashi discovers that his hero and childhood friend Obito Uchiha caused the Fourth Shinobi War, which makes killing him Kakashi's responsibility and no-one else's. An interesting example, since Naruto (the idealist) still wants to redeem him, while Kakashi and Minato Namikaze, who knew and loved him, fight only to kill. Subverted when after Obito is defeated, just as Kakashi is about to kill him, Minato stops him from doing so so that Obito can have a chance at redemption.
- Neon Genesis Evangelion:
- Shinji killing his only friend Kaworu, in order to save humanity. Kaworu actually smiles when he tells Shinji he has to die...
- The End of Evangelion takes this pretty far. Though saying that may be Cliché, there are examples to support the claim:
- During a mind probe sequence, Shinji's heart is attacked by several of his close friends — Asuka doing most of the work; as soon as his plea for mercy is rejected, he strangles Asuka.
- After this action, Shinji — having the power of God — decides to kill everyone about whom he's ever cared.
- Rei carries out his wishes.
- After this decision, every important-to-semi-important character is visited by a vision of the character they love the most only to break their Ego Barrier/AT-Field and literally destroy them.
- A noteworthy, possibly surprising example of this act is Hyuga's initial horror at the apparition in front of him before the apparition morphs into Misato and plants a wet smooch and loving caress onto him, thereby completely disassembling him physically.
- After having died several episodes prior, Kanou from Nurse Angel Ririka SOS is revived by the villainous Buros. This causes Ririka to have to kill Kanou after learning he is affiliated with Dark Joker. Ririka was in love with Kanou.
- In Occult Academy Maya is forced to behead her father's possessed corpse. He was technically already dead but the results are similar.
- It's revealed by Aokiji in the Post-Enies Lobby arc of One Piece that Jaguar D Saul (a giant that he executed for treason for protecting Robin) had actually been a close friend of his, and it's clear that he didn't take any pleasure from the act. So it makes a lot of sense in hindsight when it's revealed in the Egghead arc that Aokiji didn't actually kill him, but rather helped fake his death so he could go into hiding.
- In Project ARMS, all of the heroes say, in no uncertain terms, that they won't hesitate to kill Ryo if he's taken over by the Jabberwock. Given that he fears that happening to him, it's actually comforting. At the end of the manga, he remembers this when he has to bring himself to kill Katsumi, who is possessed by Alice. Fortunately, she gets better.
- Puella Magi Madoka Magica:
- Mami during the third timeline of episode ten's "Groundhog Day" Loop hits the Despair Event Horizon upon learning the true nature of Magical Girls after Sayaka turns into a witch and has to be killed. Not wanting the rest of the magical girls to turn like her, Mami kills Kyouko, but before she is able to kill Homura and Madoka before presumably ending her own life, Madoka shoots her. After doing that, poor Madoka collapses in tears, asking the newly released Homura between sobs why did such things have to happen.
- An even more tragic example is later in the third timeline. Madoka and Homura manage to destroy Walpurgisnacht, but both are injured, exhausted and in danger of becoming witches. Madoka uses her last Grief Seed to remove the darkness from Homura's Soul Gem in order to spare her from becoming a witch, and Homura returns the favor by tearfully Mercy Killing Madoka before she becomes a witch.
- Madoka manages to do this accidentally when she throws Sayaka's gem off a bridge to stop her from fighting Kyouko, not realizing that it literally contains her soul; though fortunately she was Only Mostly Dead. Sayaka is Killed Off for Real via this trope after she becomes a witch: Kyouko destroys her by smashing her own soul gem so they can be Together in Death.
- In RG Veda, believing that Sōma can't survive the battle and will be killed, Kendappa-ō kills her herself, and then commits suicide because she sees no point in living on without her.
- School-Live!:
- Kurumi had a crush on a boy who became a zombie. She "killed" him in self-defense.
- Kurumi tries to do this their zombified teacher, Megu-nee, however cannot bare to. Megu-nee bites her and later Miki, who is the only one who didn't know Megu-nee, 'kills' her.
- Yuuri gets dangerously close to this when she almost mercy kills Kurumi, who is becoming a zombie. Thankfully Miki appears with an antidote before she can. It still might occur in the future, though.
- In the Strider manga, Hiryu was forced to do this to his sister Mariya after she went insane and started murdering other Striders. He tried to talk her out of fighting, but being unable to, was finally forced to fight back and pierce her through with his Cypher. This would weigh heavily on his mind afterwards, eventually leading to him leaving the Striders.
- In Tekkaman Blade, all of the enemy Tekkamen are either D-Boy's family or close friends, including two brothers (one of them his twin) and a sister-in-law.
- Riddle from Undertaker Riddle killed his best friend and former king of the Catacombs, Sigurd, after he went Drunk with Power and almost destroyed the Catacombs.
