Tragedy (or Black Comedy) wouldn't be the same without a final death to close the series of murders. When the last character doesn't find death on the battlefield or by the hands of their nemesis, they can still kill themselves to ensure drama and catharsis.
Note that this trope applies both if the survivor is a victim or is the murderer.
See also Driven to Suicide, Anyone Can Die (when they actually do) and Gotta Kill Em All. Can be part of a Thanatos Gambit. A Kill Them All story might end this way. Sometimes triggered by Better to Die than Be Killed, or by Survivor Guilt. If the suicide attempt fails, then we have a Sole Survivor.
WARNING: This is a Death Trope, expect unmarked spoilers ahead.
- The last character to die in Death Note, Misa Amane, commits suicide.
- The last remaining character on Basilisk kills himself, leaving the samurai to sort out the resulting mess.
- Double-example, since the last two ninja, lovers, both intended to lose and die in the duel they'd been forced into. It could've gone either way.
- Several examples from Higurashi: When They Cry. Onikakushi-hen ends with Keiichi's suicide after murdering Mion and Rena, while Watanagashi-hen ends with Shion's accidental death/suicide.
- Tatarigoroshi-gen's Visual Novel version explains that after the Hinamizawa Disaster, only Kasaii, Shion and Keiichi were left. After Kasaii's death (from inhalation of fumes during the disaster), Shion committed suicide, and several months later, Keiichi (now in a mental hospital) also commits suicide.
- In the Detective Conan, "Moonlight Sonata Murder Case", the murderer tries to invoke the trope by trying to make it look like their last murder victim was in fact the murderer and committed suicide instead of being murdered. When the identity of the real murderer is revealed, the real murder commits suicide.
- Frank Castle kills himself at the end of The Punisher Kills the Marvel Universe after realizing that he's the only superhuman who hasn't been killed.
- Fanfic/Pokedex describes the wars of the Level X Pokémon (a shoutout to the Pokemon TCG) culminating in Flagon Lv. X, which are capable of a technique that can easily kill any other Level X Pokémon. The last Flygon Lv.X, with no other Flagon left to kill, turns the technique on itself.
- The Last Samurai ends with the assisted suicide/seppuku of Katsumoto, who is either the last or the penultimate samurai, depending on whether you count the American Nathan Algren.
- Not shown but strongly implied in the movie version of Clamp's "X" (the manga and the series left much more people alive).
- Averted in the movie version of The Mist: Driving through the endless mist, thinking that everything is hopeless, the characters decide to commit suicide. The protagonist takes a gun and methodically shoots everyone in the car, including his own son. Last, he turns the gun on himself... only to realize that he's out of bullets.
- Played with in Penn & Teller Get Killed: the titular duo get the titular killed after a series of pranks which Penn set up to pretend that someone was out to kill him; the actor Penn hired kills himself because Penn set it up so well that nobody will believe that he didn't kill Penn & Teller. The actor's friend, a would-be politician who came to the post-performance party, kills himself because his career is over before it even began. A pair of cops show up; one takes the Vomiting Cop routine to its ultimate conclusion, killing himself, and the other one does too. Fade to Black as more and more people come across the crime scene and kill themselves. So you think that each one would be the final suicide, but it just keeps going.
- Open Water. Susan gives up and drowns herself after her husband Daniel dies.
- Serenity: The Apocalyptic Log that the crew finds on Miranda has a researcher attempting this, but she is interrupted by the Reavers.
- And Then There Were None uses this trope twice. First, after witnessing the murder of her companions of misfortune, Vera Claythorne finally snaps and hangs herself out of guilt, thus completing the series of deaths with a suicide, following the original rhyme. Then it becomes clear that the murderer was still alive after her death, but the trope is finally played straight once again because U.N. Owen kills himself too in the end.
- Of course, the nursery rhyme provides the page quote.
- Brave New World: John the Savage hangs himself, and the novel closes on his corpse being found.
- The X-Files: The last of a group of astronauts who had been traumatized during their mission chooses to kill himself after various gruesome deaths (including other suicides) take out the rest of them.
- Criminal Minds episode "Reckoner" played with this trope. A Hanging Judge organized the murders of some Karma Houdinis that had managed to evade justice, and put his own name on the list because he was going to die anyway of cancer. In the end, he didn't kill himself but was sniped by the mobster he had hired to kill the other victims.
- In The Walking Dead, there is only one surviving scientist left at the CDC headquarters after a Zombie Apocalypse. He's watched his colleagues be infected and killed, run off (and presumably die), or suicide until he was all alone. By the time the protagonists find him, the generator is nearly out of fuel and the CDC is less than a day away from self-destructing. He knows it's going to blow, but chooses to stay and end it rather than leave.
- Frobisher kills his family and then himself in Torchwood: Children of Earth.
- Ultimate Showdown of Ultimate Destiny ends with Mr. Rogers committing seppuku.
- William Shakespeare, of course, used this trope in his tragedies:
- Othello: Othello stabs himself.
- Julius Caesar: Brutus kills himself in the end through running himself on another's sword (since his Stoic philosophy forbade him from directly committing suicide), though it's unknown how many of the other conspirators were hunted down and killed off hand.
- Hamlet narrowly averts this (or maybe it subverts it); at the end Hamlet's friend Horatio is so overwhelmed by the events of the plot that he tells a dying Hamlet that he's going to kill himself; Hamlet tells him not to, he needs to be the Sole Survivor to tell Fortenbras that he (Fortenbras) is now the king of Denmark.
- Subverted in Final Fantasy VI. After Cid dies, Celes is left alone on an island, potentially the last person left alive on the planet besides Big Bad Kefka. Unable to cope with the loss, Celes climbs to a high cliff and throws herself from the top, intending to kill herself. However, she survives the attempt, and sees a seagull with Locke's bandanna, giving her hope that someone else is still out there.
- One of the endings of Spec Ops: The Line. Going by the Steam statistics, it's also the one most players went with.
"I know the truth is hard to hear, Walker, but it's time. You're all that's left, and we can't live this lie forever."
- In Mass Effect 3, if you side with the geth over the quarians, the Migrant Fleet will be wiped out. Tali, with Shepard at the time, kills herself, and not even the Paragon interrupt can save her.
- In The Order of the Stick, Xykon uses a Symbol of Insanity to force a large crowd of paladins to fight one another to the death. When the last surviving paladin recovers from the symbol's effects, she commits Seppuku Atop a Mountain of Corpses.
- The Simpsons once made a ripoff of Hamlet that ended with Marge (portraying Gertrude) killing herself not to clean up all the mess.
- South Park uses this as a frequent gag/Deus ex Machina.
- School and other mass shootings often end with the perpetrator(s) shooting themselves. That's enough.
- Inverted with the Nuremberg trial: Hermann Goering poisoned himself before the death sentences were carried out, since he would have been the first one to be hanged.
- In the siege of Masada the residents of the Masada decided to kill each other because they didn't want to be taken prisoner. They killed each other instead of themselves because suicide is a grave sin in Judaism (their religion). Predictably may have left one guy left who had to kill himself (most notably, at the Siege of Yodfat, the historian Flavius Josephus was able to do some very complex math on the fly and positioned himself in such a way that he was the last man standing, Josephus later surrendered to the Romans). It may be noted that there were far fewer skeletons found in Masada then the stated number of people who killed themselves, so the mass suicide thing might just be a myth.