This is when a character leaves/abandons someone that they were close to, maybe out of a obligation, personal reasons, or not by their own choice note Maybe a character is a Living Emotional Crutch or a Morality Chain to them. Maybe they have implied romantic feelings for them. Maybe they were a pair of True Companions, or family. In some cases, the person left behind may not even have realized their feelings until the other left.
In any case, the character who is abandoned for whatever reason goes crazy after the other leaves them. So this is more like the end result of a characters Living Emotional Crutch leaving them.
Sometimes, if the abandoned character eventually learns the gone character came back or did not actually die they may regain some of their sense of stability, or not if they are so far gone or resentful from the characters disappearance.
If the "gone" character is still alive, the "crazy" character may decide that I Will Find You, which may lead to Roaring Rampage of Rescue... but if the "gone" character is well and truly dead, the "crazy" character might actually go the other route.
Supertrope to Psycho Ex-Girlfriend and Angsty Surviving Twin. Compare Go Mad from the Isolation and Loners Are Freaks, where somebody goes crazy because everybody's gone (or if someone's especially lonely, this might actually end up being the result anyways).
- Attack on Titan: Whenever Eren, who is a reason for living for Mikasa (ie: due to him and his father taking her in and saving her from being sold as a sex slave after some bad people killed her parents) is assumed dead or is kidnapped, Mikasa goes mad with both grief and rage, intending to cut down any enemy in her path to get him back (or simply attack blindly until she's killed).
- Berserk: Griffith gradually becomes obsessed with his best warrior Guts, such that when Guts decides to leave the Hawks after deciding that he's not going to be a part of Griffith's dream, Griffith's thoughts during the resultant duel, about how he would not let him go, are very unhinged; when Guts beats him in the duel and wins his freedom Griffith cannot take it and immediately goes to sleep with Princess Charlotte, while thinking about Guts and his leaving the whole time. In fact, the events that set into place his downfall and lead up to the horror that is the Eclipse, is caused partly by Guts leaving.
- Hellsing: Zorin makes a point to kill Pip after maiming Seras. The two share a Last Kiss and at his (Pip) request Seras drinks his blood in order to become a true vampire. This, coupled with Seras anger at losing Pip, allows her to utterly massacre Zorin and her forces.
- Naruto: Sasuke lost his family from his beloved brother Itachi killing them at a young age. He went crazy understandably and sustained himself with the goal of getting revenge. He eventually does see to it that Itachi dies but learns the truth that Itachi loved him all along and killed their family under an order from the higher ups for the sake of the Konoha leaf village. Sasuke goes insane from that, in addition to him losing Itachi. His sanity is restored somewhat only when Itachi is briefly brought back to life. When Itachi gives Sasuke a final brotherly goodbye and disappears Sasuke promptly goes crazy again.
- Obito over his crush Rin. When Rin kills herself by jumping in front of Kakashi's attack, Obito decides to destroy the world in order to create a new one where Rin is alive.
- Neon Genesis Evangelion:
- Gendo Ikari has this mindset. He is obsessed with his dead wife Yui, he doesn't care if the world is destroyed by his meddling with Gods who can cause the Apocalypse, as long as he can see Yui again.
- Shinji Ikari takes after his father. In "End of Evangelion", when he sees that Asuka is dead he stops fighting, not caring what happens to the rest of the humanity.
- In Rebuild of Evangelion, when Asuka's Eva is taken over by an Angel, Shinji refuses fighting because he doesn't want to hurt her, and when his father forces his robot to destroy the Angel, seemingly killing Asuka, Shinji attempts bringing Nerv down and killing everyone inside the base, not caring that it is humanity's last line of defense. And when later it is Rei's turn to be absorbed for an Angel, he activates his robot's full power, even though Ritsuko warned him that it would set off the Third Impact. Basically, Asuka and Rei are two of the few people Shinji cares about. Hurt them and expect pain.
- When Mika and Yuu, who are the others most important person, are separated in Seraph of the End for dramatic purposes involving both being orphans with the rest of the orphans who they considered family being killed before their eyes by the vampires that enslaved them. They cling to the others memory to use as a source of strength in order to the find the other again. However, both can get pretty unhinged when it comes to the other possibly being separated from them again.
- Guren lost his friends to death once so he sacrificed nearly every human being left after the apocalypse for the chance to revive his friends and give them at least a few years of life.
- Tengen Toppa Gurren Lagann: Kamina and Simon are close like family, and then in one episode (after Kamina's death, that is) Simon is shown spending his time making statues of Kamina and nearly filling up his room with them.
- Tokyo Ghoul:
- Mutsuki has a horrible past where he was abused by his father and neglected by his other family during it. He snapped and killed them all. As he says, when he joined up with the Quinx afterwards and became close with them he felt almost whole again. He clung especially to Kaneki/Sasaki as his Living Emotional Crutch and even loved him. Thus, when the latter leaves to return to the ghoul side (not entirely of his own choice) Mutsuki falls to pieces and loses it.
- Tsukiyama falls into a Angst Coma after Kaneki leaves him and the others to try to sacrifice himself for his companions sake. He goes crazy from Kaneki leaving and possibly dying, and nearly dies himself from his self destructive behaviors until he regains the will to live as soon as he learns Kaneki still exists.
- The Dark Knight Returns has a very creepy example. The Joker was crazy to begin with but when he contemplates a world without his nemesis and obsession Batman he falls into a catatonic shock and only hearing about Batmans activities in the news is enough to revive him.
- In The Sandman, a schism grew between the younger and older members of the Endless after their "prodigal sibling", Destruction, abandoned his post for good. Without Destruction, Desire became more and more interested in tormenting Dream, while Destiny and Dream grew aloof and distant from their younger siblings.
- The Crapsack World inadvertently created by Flash in Justice League: The Flashpoint Paradox has Martha Wayne become Joker in response to losing her son Bruce, who here dies instead of his parents.
- In Steven Universe: The Movie, Spinel was Fun Personified when she was created, and told by Pink Diamond to wait in one spot until she got back. Six thousand years later, Spinel still hadn't moved, and learned that Pink Diamond was dead, had moved on, and made other friends. This caused Spinel to snap, wanting Revenge by Proxy on Steven. Even after being reverted to her old self, the very idea of someone leaving her — even if it's only for a few minutes — is so terrifying to Spinel that she lets out a Big "NO!" at the mere suggestion.
- In A Mighty Wind, the reunion concert includes Mitch & Mickey, a former couple that released seven albums until their dramatic break-up years before the setting of the film. Mickey seemingly moved on and has married a medical supply salesman, but Mitch had an emotional breakdown and has never fully recovered.
- Rectify: Its revealed that ever since Hannah died in a horrific way, her mother has been unable to get over it, and spends her days religiously walking around and moving things in her daughters room obsessively with her son watching on, very concerned for her.
- An interesting case occurs with the Doctor in Doctor Who; only on two occasions has he been shown without a companion or a companion surrogate for an extended period of time, and in both cases it resulted in a more unhinged and dangerous Doctor.
- The first instance was with "The Deadly Assassin", in which the departure of Sarah Jane, the heated political turmoil on Gallifrey, and the Doctor's discontent at his home society result in a moodier, brooding, and more aggressive Doctor whose portrayal emphasizes the darker aspects of his madness, making it clear that the lack of a Morality Pet has left him noticeably unhinged.
- The second and more noticeable instance was with "The Waters of Mars". Again, the Doctor is without an acquaintance to keep him in check, his most recent regular companion being forced to leave him for her own protection and his last three companion surrogates refusing to continue traveling with him. However, being riddled with trauma from fighting a violent war and seeing his ideals and purpose challenged time and time again over the centuries has torn at his ability to keep himself in check. As circumstances seem more and more futile, he grows increasingly aggressive and unhinged, eventually deeming himself the "Time Lord Victorious" and the master of the laws of time. Only after he attempts to break said laws and sees them sharply set back on track does he realize that he's gone too far.
- The song "They're Coming to Take Me Away" is about the singer blaming his Sanity Slippage on his girlfriend who dumped him, saying that the "nice young men in the clean white coats" are coming to take him to a mental hospital. An alternate song, "I'm Glad That They Took You Away" takes place from the perspective of his girlfriend, who sent the "nice young men in the clean white coats" to him in the first place.
- In Ensemble Stars!, Izumi used to be a kind older brother figure to Makoto, but by the time the story starts he has become an obsessive, cruel Yandere. It's implied that this change was a consequence of the mental breakdown and disappearance of Leo, his closest friend.
- Played with regarding the Skull Kid in The Legend of Zelda: Majora's Mask. A big part of his character is his friendship with the four guardian giants of Termina; he became friends with them, but they had to leave to fulfil their duties, which the juvenile Skull Kid misunderstood as abandoning him and developed a complex over. This resentment festered until he picked up the titular Majora's Mask, which took his worst desires and behaviours, and amplified them to apocalyptic levels. One of the things he did was to seal away the spirits of the four giants; this was done partially to prevent them from stopping Skull Kid's planned moon drop, but it was heavily driven by his resentment towards their perceived abandonment.
- Suna Silentstrike in World of Warcraft is noticeably distraught when her husband Lin, who she refers to as the "light of [her] world," goes missing after an attack by the yaungol. When she discovers he's been killed, she goes into a rage, which makes it easy for her to be possessed by the Sha of Hatred and turn on the player character and the Shado-Pan, who she blames for not doing enough to protect Lin. Eventually, the player is forced to kill her as well.
- Yggdrasil in Tales of Symphonia went off the deep end when his older sister, his surrogate parent and only living relative, was murdered in front of him. His response was to embark on a four thousand year plan to resurrect her while also turning the entire world's population into soulless automatons in order to eliminate racism.
- Avatar: The Last Airbender: Ty Lee and Mai decide they want to be out of the iron grip of Azula and try to leave her. This is the start of her downfall.
- In the Gargoyles episode "Future Tense", an illusion of the future shows that the clan fell apart in Goliath's absence (for the World Tour and other events in Avalon) and then Lexington went berserk and tried to take over the world.