So something bad is about to happen; a nuclear weapon is about to go off or an asteroid is about to impact the planet, and the only way to avoid this is if someone stays behind and sacrifices themselves to stop it. But who will go? All of these characters are lifelong friends. There's no easy way to decide. Or is there? One of the characters has an Incurable Cough of Death and only a few months to live. They'll do it — after all, he's dying anyway, and in a far less dramatic and spectacular way.
This trope is about when a character gives their life for something based on the reasoning that they're going to die soon anyway. It's a favorite for when a writer wants to make a bittersweet ending less bitter.
Occasionally, the doctor will burst in just a second too late to explain that he tested the wrong vial and the character isn't (wasn't) going to die. Oh well, it's too late now!
As this is a Death Trope, unmarked spoilers abound. Beware.
- Played straight with Kimimaro, who dies with his weapon just centimeters away from piercing Gaara's eye. If he was that fast and strong when he was dying of terminal illness, then think about how fast and strong he was when he was healthy.
- Subverted later in the Sasuke vs. Itachi fight. Itachi appears as though he's about to kill Sasuke, when he keels over dead after coughing up copious amounts of blood throughout the fight. But then it's revealed that even if he hadn't died from his illness, he wouldn't have killed Sasuke anyway. Especially convenient for anybody standing in Itachi's way; when he was healthy, he completely wrecked two of Konoha's strongest shinobi without breaking a sweat.
- Fullmetal Alchemist:
- Hohenheim offers to do this to bring Alphonse back since his ontological inertia has been broken down in the battle and he is dying anyway. Ed refuses and sacrifices his own ability to do alchemy instead. Hohenheim went and died smiling on his wife Trisha's grave instead.
- In Fullmetal Alchemist: The Conqueror of Shamballa, Hohenheim does this incomprehensibly.
- In Dragon Knights, Kaistern had already been corrupted by contact with demon water and his body was rotting anyway, giving him limited time left. So he offered his life force up to Cesia to give Rath to resurrect him.
- Early in the X-Men comics, Professor Xavier died. Then he returned. It was explained via flashback that a terminally ill mutant scallywag calling himself the Changeling offered to pose as Xavier so the Prof could prepare for an imminent invasion. Jean knew, so as to help the shape-shifter better pass off as the X-Men's mentor.
- In the Fantastic Four storyline Reckoning War, this basically applies to Reed Richards' temporary acquisition of the full knowledge of the alien Watchers; while the knowledge was going to kill him, it also allowed Reed to use the Ultimate Nullifier to end the current conflict, the weapon draining Reed's Watcher knowledge and powers while returning him to his original intellectual level.
- In MGLN Crisis, the clones of Miyuki and Kyouya, according to Shamal, have about a year to live. They make a Heroic Sacrifice toward the end of the fic.
- Definitely describes Buffy's reasons for going into what she believes will be her final fight in the Angel/The Hunger Games crossover "Demon's Games"; Buffy has recently learned that she Came Back Wrong after her recent resurrection and knows she will die soon due to complications from the process that brought her back. As a result, when circumstances require someone to engage in a fight on the Astral Plane and appeal to the soul in the Key of Dagon, Buffy volunteers despite her lack of experience in this kind of fighting, as she's so close to death it doesn't matter if she can't come back to her body, and this way a strong fighter with a connection to Dawn can take on the challenge and the Summers sisters can pass on to the afterlife together.
- Resident Project: In the first chapter, Leon gets bitten by a zombie, and several times over the next few chapters, he volunteers for dangerous missions because he's on a ticking clock anyway. And then it turns out that due to a unique combination of heritage and history, he is the one person in a trillion who is immune to the zombie virus.
- Played with in Madagascar: Escape 2 Africa with Melman also going to jump into a volcano. Also never sick.
- Near the beginning of Space Cowboys, Tommy Lee Jones' character is told he has pancreatic cancer with only eight months to live. The only way to save the world from a Russian satellite armed with nuclear missiles is for somebody to fly it into the moon. Since he is dying, and going there has been his lifelong dream, guess who volunteers.
- At the end of Gran Torino, Walt tricks the local street gang into shooting him to death in front of all the neighbors so that they'll all go to prison. Earlier, Walt is revealed to have a serious but unnamed condition that causes him to cough up blood.
- The Gray Man (2022): Six goes to see his trusted retired boss Margaret and discovers she has only months left to live. When those hunting him down converge on her apartment she helps him sneak out but tricks him into leaving her behind, and then she blows up the apartment when she's lured most of the mercenaries inside with her.
- The entire point of Joe Versus the Volcano, with a twist: he was never sick.
- In Repo! The Genetic Opera, Rotti Largo is told that whatever illness he has is terminal, so he sets the movie's plot in motion, namely naming Shilo as the heir to Gene Co. He dies at the end of the movie.
- In Red (2010), Joe volunteers to be the distraction for the protagonists to escape from a house that is surrounded by the CIA. He mentions earlier in the film that he's 80 years old and has stage 4 Liver Cancer, so he chooses to make "the hard choice".
- In Crooked House, Lady Edith learns that she is dying of cancer, and decides to kill herself by driving her car off a cliff. She takes Josephine with her because she knows that Josephine has committed two murders and, if not stopped, will commit more. If she is caught, Edith knows Josephine will spend her entire life in an institution. Edith leaves behind a note confessing to the murders so that Josephine will go to her grave with her name unbesmirched.
- In Cold Pursuit, Nels' brother Brock is dying of cancer. When Viking mistakenly concludes that Brock is the one who has been killing his men, Brock confesses: taking the fall for Nels and dying in his place.
- Something similar almost happens in Galaxy Quest — at least, if being the designated Red Shirt counts as a terminal condition. Guy certainly thinks so when he volunteers himself for a Heroic Sacrifice. Fortunately for him, Fred tells him that he's actually the Plucky Comic Relief — and comes up with a better idea anyway.
- Life as a House: After losing his job, George learns he has terminal cancer so advanced that he only has about four months to live. In the time he has left, he resolves to reconnect with his estranged teenage son and to build a new house in the place of his current ramshackle dwelling.
- After Snape kills Dumbledore at the end of Harry Potter and the Half-Blood Prince, readers are informed in Deathly Hallows that a curse on Dumbledore's hand from one of Voldemort's horcruxes was slowly killing him. He had ordered Snape to kill him so that Draco wouldn't have to do it, thus saving Draco's soul (and the Malfoy's lives if Draco isn't able to go through with it). Interesting in that the character is not revealed to have been critically ill until after his death (though there are hints).
- Another example where readers find out after the fact: In The Dresden Files (Death Masks), Harry is being held in a completely inescapable position by Nicodemus, who offers him a choice between joining him or being killed. That's when Shiro barges in and offers himself in Harry's place, letting the Denarians torture him to death. A couple weeks after everything goes down, Harry gets a letter in the mail: Shiro had terminal cancer and only a few months to live.
- In the novel The Wishsong of Shannara, the Borderman Helt is attacked by a huge bat creature that scratches his face. He insists that he's okay, but not long afterward, he sacrifices himself to buy time for his comrades to escape from a horde of enemy Gnomes. Garet Jax later explains that Helt had been poisoned by the bat creature and knew he was dying.
- The very first Sherlock Holmes story uses this- the murderer has Watson confirm his fatal heart condition after he's captured and dies before facing trial. Since the victims are responsible for the murder of his fiancee and her father, and were horrible human beings in general, little is made of the case.
- At the climax of Calibans War, James Holden boards an enemy ship infected with protomolecule to activate its Self-Destruct Mechanism but finds out this mechanism has no countdown; the ship will blow up the moment it's activated. It just so happens that an officer who tagged along got infected with protomolecule along the way, which means he's doomed anyway and thus won't mind engaging self-destruction once Holden gets to a safe distance away from the ship.
- In 24, CTU Director George Mason gets a fatal case of radiation poisoning while searching for a nuke in Day 2. At the end of the Day, Jack flies an airplane carrying the nuke on a suicide course to the desert to prevent it from killing anyone, only for a stowaway Mason to reveal himself, convince Jack to not throw his life away, and take his place at the controls while Jack parachutes to safety. It helps that while Mason was dying, he looked back on his life and realized how much he had made everyone close to him dislike him, which caused him to try and make amends with his remaining time. Being poisoned not only gave him a reason to sacrifice himself in another's place (he says that he'd rather not suffer the end-stage poisoning effects) but most likely was why he would even consider doing so.
- Chernobyl: One of the reasons that Legasov goes to great lengths to stop the Chernobyl accident from being covered up despite what the KGB could do to him is because overseeing the cleanup exposed him to enough radiation that he probably has less than 5 years to live anyway.
- Dead Man's Gun: In "Death Warrant", Katherine Morrison takes advantage of the fact that is dying and has three months to leave to frame John Pike for her murder: ensuring that he will not live much longer than hers, and thus avenging her son.
- Diagnosis: Murder: In "Murder Country Style", a mother confesses to a murder committed by her daughter in an attempt to keep her daughter from going to jail, since she has a terminal illness and is OK to spend whatever remains of her life in jail for the sake of her daughter's freedom. Unfortunately for her and her daughter, Mark figures out that her testimony is a lie since her condition has left her too weak to swing a blunt instrument with enough force to kill.
- Harrow: The mother in "Pia mater" ("Gentle Mother") is dying of terminal cancer when she deliberately crashes her car, killing herself and her adult son. Harrow's investigation reveals her son was a burgeoning Serial Killer when she attempted to kill him in his teens; her bullet lodged in his frontal lobe, causing a drastic personality change. Years later, an accident caused the bullet to shift and his original personality started to return. The mother, dying of cancer, decided to finish the job she started years earlier by killing them both.
- Money Heist has a variant in that the ill character willingly goes ahead with the sacrifice with the others never thinking about it in the first place. In the final Season 2 episode, Berlin, who has Helmer's Myopathy, is the only member of the heist team at the Royal Mint of Spain who fights against the incoming armored police squad to give time for the rest of the robbers to run to the exit they made. He ends up being shot down by the squad.
- In the series finale of Revenge (2011), Emily is framed for murder by Victoria and forced to flee the police. After Victoria sics her henchman on Emily's lover Jack, Emily becomes determined to end their cycle of retribution by killing Victoria once and for all. She corners Victoria in her hiding place and is about to pull the trigger, despite the presence of cameras that will incriminate her for real. However, her father David sacrifices himself by killing Victoria instead, as he is already dying from terminal lymphoma. He ends up getting compassionate release on account of this and gets to die as a free man.
- In an early episode of Stargate Atlantis, the Atlantis expedition are helping the Hoffans develop a drug that they believe will make those injected with it immune to being fed on by the Wraith. Once the first test sample of the drug has been created, the initial test subject is a Hoffan man dying of a terminal illness, who Doctor Carson Beckett affirms can't be treated even by Atlantis's technology. A scene is dedicated to Beckett and his Hoffan colleague, Perna, talking with the man to get his informed consent for his use as a test subject of the drug, as they explain that they can't know if the drug will work in its current form and Wraith feeding will be a painful way to die if it doesn't work. In the end, the man accepts despite the risks, explaining that as he's dying anyway he doesn't have much to lose, and even if he dies because the drug doesn't work his death will allow the doctors to learn more about the drug for later development.
- In Star Trek: Deep Space Nine, Worf volunteers for a Last Stand to buy time for the rest of his crew to escape from some pursuing Jem'Hadar ships. But the old, ailing war hero Kor knocks him out, steals the ship, and takes on the Jem'Hadar himself so that he can properly die in battle instead of wasting away in bed.
- Vera: In "Young Gods", after the killer is caught, he confesses to Vera and then adds that he will not live to stand trial. He has lung cancer, and has three months to live; six at the most. He received the diagnosis the same day that he learned the information that caused him to commit murder, and took it as a sign.
- Warehouse 13 had a variation, in which an old man uses a butcher knife that formerly belonged to "Typhoid" Mary Mallon to transfer his son's terminal leukemia to himself. He hadn't previously been terminally ill himself as such, just old, but he clearly considered the few remaining years of his own life he would be losing were a small price to pay to make sure his son lived a full one.
Owen Larsen: It wasn't fair. Now it is... I couldn't just let him die. He has a little boy... My boy's life is just starting out. He can watch his son grow up, protect him. Now it's fair.
- In Final Fantasy X, Seymour's mother indirectly cites this as being part of her willingness to sacrifice herself to become his Final Aeon, with which he could destroy Sin and save the world. Uniquely for this trope, it manages to backfire spectacularly, because what any outcast Half-Human Hybrid needs is for his mother to lay the weight of saving the world on his shoulders as she kills herself/leaves him forever. Is it any wonder he winds up a Woobie, Destroyer of Worlds?
- Subverted in Dragon Age: Origins. Near the end of the game, it's revealed that only a Grey Warden can kill the Archdemon, and only at the cost of their own life. Riordan volunteers, reasoning that he has been a Grey Warden for much longer than Alistair, Loghain, or the Player Character, and only has a few months left before the Darkspawn Taint takes him anyway. The other characters seem to agree with this. However, Riordan ultimately fails to kill the Archdemon, leaving you in the same Someone Has to Die situation you were in before.
- Ion in Tales of the Abyss conveniently comes up with a case of Almost Dead Guy from being killed by Mohs at the point where Tear's illness is beginning to kill her, allowing him to use a Heroic Sacrifice to purge her body of the illness at the cost of his own life. For a double whammo of this trope, he was an unstable Replica to begin with and probably didn't have much longer to live anyway because of it.
- The Plot-Triggering Death of Laphicet in Tales of Berseria turns out to be this. Eleven-year-old Laphicet was born with the Twelve-Year Sickness, which causes deteriorating health all through childhood to the point that most carriers of it die before their twelfth birthday. As such, he volunteered to be the Human Sacrifice used in Big Bad Artorius' ritual. Only problem is, he failed to inform his older sister Velvet about any of this, so from her point of view it was a cold-blooded murder - and she only finds out otherwise three years, a lot of physical and mental trauma, and one Roaring Rampage of Revenge later. Predictably, she does not take the revelation well.
- Played for as much Tear Jerker potential as possible by Metal Gear Solid 4, where Snake's terminal illness and Incurable Cough of Death make him reckless, self-destructive, and occasionally outright suicidal, dead set on performing a Stupid Sacrifice. It's also made painful by the fact that his terminal illness means that even if he does survive all the stupid things he keeps doing to his body - which of course he knows he will - the beloved character himself is not getting out alive.
- There's a variation in Red Dead Redemption II. The things Arthur does in the final chapter probably wouldn't be fatal if he didn't have end-stage tuberculosis, but getting the terminal diagnosis galvanizes his character development and gives him the courage to break away from Dutch, whom he was genuinely loyal to despite Dutch's declining sanity. Had Arthur never contracted TB, he probably wouldn't have tried to help John and Abigail escape.
- Danganronpa V3: Killing Harmony gives us Kaito Momota, whose secret Incurable Cough of Death drives most of his character. It's why he wants to become an astronaut despite being so young. It's why he lives every day as though it might be his last. It's why he exercises every night. Finally, it's why he cooperates with Kokichi in the latter's plot to fight the killing game itself. While that plan fails utterly, he's notable for being the only killer in the franchise who is found guilty but isn't successfully punished. He dies partway through his execution and judging by the final facial expressions of Kaito and Monokuma, Kaito got the last laugh.
- In Gene Catlow, a boy with brain cancer who hates furries frames them with his suicide. It doesn't end well for him.
- Unsounded: Elan Aled decides to stay and fight against a foe he cannot possibly survive against to give Elka and Toma a chance to escape Bell's purge of Ethelmik, a decision backed by the fact that he's already dying of a heart condition and hasn't been able to get his medicine for two days.
- The Hair Bear Bunch episode "Rare Bear Bungle" has Bubi Bear faking what sounds like a terminal illness as a stop-gap measure to deflect Mr. Peevly while Hair concocts a plan to replace and locate a $50,000 bear they sent into town.
- There's an episode of Teenage Mutant Ninja Turtles (1987) with Raphael as the one who heads inside a volcano to keep a bomb from being set off in it while (falsely) believing himself to be dying. More than likely as a Shout-Out to Joe Versus the Volcano; the title of the episode is "Raphael Versus The Volcano."
- In Transformers: Cyberverse, in the episode "Terminal Velocity", Bumblebee, Hot Rod, and Blurr seek to escape Velocitron which gets destroyed by the Rust Plague. Eventually, they reach the Space Bridge, where they are about to leave, but somebody needs to stay behind to keep the bridge open. Blurr volunteers, declaring that Velocitron is his home and that he himself already fell victim to the Rust Plague. He eventually crumbles to dust, but still managed to prevent the Rust Plague from spreading.
- An downplayed example with old age instead of illness occurred after the Fukushima nuclear power plant meltdown. A corps of retired Japanese veterans and engineers, all 60+ years old, volunteered to assist with the cleanup and repairs. The trope is downplayed, as the primary point is that an elderly person's body's cells divide slower than a young person's, making them somewhat less susceptible to radiation poisoning, but the trope still applies in that it takes five to ten years for radiation exposure to develop into cancer, and by that time a senior will be well into advanced age and only need to live with it for a decade or two, while a young person will have to live with it for fifty years or longer.