- A Crown of Stars: In chapter 8 Shinji and Asuka find an alternate Shinji who had been tortured to the point he was dying, forcing Asuka (who had gone to rescue him) to give him a swift death (and then he got better. Long story)."We got to Shinji, but he was, was... Tears began to drip onto their joined hands. ...dying. We gave him mercy... He died in my arms. Dont let yours go."
- Darling in the FranXX: Homecoming: In the first chapter, 059 finds the same wounded bird Hiro passed when he met Zero Two, and seeing its condition and how it most likely won't fly again, snaps its neck to put it out of its misery.
- In Chapter Seventeen of Tiberium Wars, Brother-Captain Alvarez of the Black Hand is torn between engaging in a Last Stand to evacuate a small number of wounded troops, or saving his men by ordering a retreat and leaving the wounded to be captured by GDI, who he believes will torture and kill them. He instead chooses a third option: executing his own wounded to keep them out of GDI hands.
- A Tear Jerker moment in Aeon Natum Engel: Two persons consider doing this to their dying 5-year old half-sister, neither of them is able do it, and break down in tears.
- Heavily implied to have happened with Gohma in "The Legend of Zelda: Ocarina of Time". Early on, Ganondorf threatens to curse the Great Deku Tree, which would turn it evil and leave it in "constant, never-ending pain until [his] slow death arrives". After realising that such a curse would not work on such a pure deity, he redirects it at a nearby crust spider which transforms it into Gohma. If what Ganondorf said was true then that crust spider was suffering in agony until Link unknowingly put it out of its misery.
- A Feddie Story has one of the tanks brew up after getting hit by a Zaku. The driver gets out safely, but the commander is on fire by the time they bail out. They roll on the ground for a moment before the gunner of one of the other tanks machineguns them rather than watch them burn to death.
- Happens to Brock and Ash during the course of Carnage Necropolis, after they're infected.
- Night of the Shy: Birostris Oswaft, the last of the Sand Mantas, begs Twilight to do this to him, as he wants nothing more than to join the rest of his people in death.
- Superwomen of Eva 2: Lone Heir of Krypton: In chapter 20 Asuka did it to Kaworu at his request.
- The Pony POV Series: This comes up during the Final Battle with Princess Gaia/ Nightmare Whisper. Both Rarity and Rainbow Dash decide they have to kill her, not out of hate, but because they both figure Fluttershy would rather die than see what she's become.
- During the Epilogue/Dark World timeline, Apple Bloom apparently ended up subjected to the same curse as Sunny Town. After eventually helping the entire town free themselves from the curse and move on, she begs Liarjack to do the same for her so she can be with her family; reluctantly, LJ agrees, and Apple Bloom dies.
- This rationale is how his allies comfort Shining Armor for having killed one of Makarov's Alicorn cyborg Co-Dragons, by pointing out that the poor soul was in a living hell.
- Apparently one of Entropy's, the Elder God of the End, jobs is to do this on a cosmic level to universes that have been abandoned by their Shadows Who Make before maturing enough to exist on their own (which basically results in them continuing what they were last doing for eternity, unable to die or change what they do), as it's a mercy compared to that fate.
- The Fall of the Fire Empire: When Ozai descended into senile madness, Azula smothered him with a pillow. Qing Xi describes it as the only merciful act of her life.
- The Powers of Harmony: After Eclipse fatally poisons him, condemning him to a slow and painful death, Strauss requests that Granny Smith put him out of his misery. She reluctantly complies.
- In Cheerilee's Garden, after Cheerilee submerges Pinkie Pie into a container full boiling hot water, she convinces Rainbow Dash that it would be better to put her out of her misery rather than to let her go on living.
- Discussed in the Berserk fanfic "The Entire World is a Battlefield" when Guts is met by a spectre of pre-Eclipse Casca. While the real Casca is not dead, she is mentally gone, and Guts wonders if the current Casca is better off dead after what she experienced.
- The Fall of Cleveland has Marshall find a hideously tortured fluffy pony in the chapter "The Facility". It begs for help, but it's so horribly maimed that Marshall can't think of a way to help it. So he does the only thing he can and breaks its neck. The fluffy's last word is "Ffffffffffannnnnnkkkkkkkk..." (Fluffies can't pronounce "th" sounds.)
- Mammoth does this for Plasmius/Otto von Furth in Consequence of Misunderstandings after Slade makes it impossible for him to sleep (and thus stay human). Gizmo mentions that while Raven's healing powers do prevent most of them, the team has had to perform mercy kills before.
- In Constant Temptation Light does this for his father, he writes his name in the Death Note after his father has been kidnapped and tortured to breaking by Beyond Birthday before Beyond was finished hacking pieces off of him.
- Played with in the Left 4 Dead fic Acts Of Mercy. Originally, it's implied that the titular 'Act of Mercy' is Marcy saving Den from the barbed wire fence; later on, it's when she is forced to kill Denver after he tries to attack her. Ultimately subverted, though, since the CEDA intervenes before she does the deed.
- In "From Bajor to the Black, Part II", Eleya guns down a shipmate who's in the process of being assimilated by the Borg.
- The Second Try: Shinji and Misato stop Ritsuko from activating the control that destroys the soulless Rei clones in the Dummy Plug system, so Rei does it herself.Rei: These are not human beings. Their official purpose is to serve as core for the Dummy Plug system, but even that is only secondary. As Dr Akagi explained, they are mere vessels to hold my soul. That was the only reason they were created for, just like the body I possess now and the ones before. Without a soul, they can not become aware of their feelings. They notice the feel of the warm LCL around them, of this glass holding them; they can see us, the world outside of theirs. But... it does not matter to them. All they are doing is existing, blissfully unaware of everything. They cannot understand the difference between pain and joy. They do not know the vast variety of human emotions. They do not feel hope or fear for the future. I always wondered whether to pity or to envy them. (pushes the button)
Shinji: Rei... What have you done?
Rei: I have... set them free...
- In Sean Bean Saves Westeros, the "real life" Sean Bean is transported into the land of Westeros of A Song of Ice and Fire. Now living as Ned Stark, not just playing him on TV, Sean Bean sends Westeros Off the Rails. In the aftermath of the Battle of the Green Fork, Sean has to give a Mercy Kill to a mortally wounded Tyrion Lannister.
- Tails's death in Episode 77 of Sonic X: Dark Chaos is this after he sacrifices himself to stop Dark Tails and suffers And I Must Scream because of it.
- Eggman and his robots terminate Beelzebub's "test subjects" in the Episode 67 rewrite.
- In My Little Pony Crossover MLP Trinity, Sweetie Finemare administers a fatal overdose of opiates to her dying husband Rich Greentree, to spare him further agony.
- In the Ask Serious Rainbow blog this is the real reason Green Eyes (Pinkie) had killed Serious: in her old universe Twilight went insane and tried to kill her friends, and it was too late to save Serious. She asked Green Eyes to put her out of her misery before she died of blood loss.
- At the end of a trilogy of walfas Touhou shorts titled Regret, we find out that Reisin performed this on a younger moon rabbit soldier to spare her from being killed and eaten by mohawk zombies (it isn't clear as to exactly what they are) when she is almost out of ammo and while they take shelter in an abandoned bunker while the horde closes in. However, had she held out a little longer, both she and the younger rabbit soldier could have been saved.
- Discussed, but ultimately averted, in the Thunder Cats fanfic "A Right to Death". A deadly disease, the main symptom of which is unrelenting pain, breaks out on Third Earth. Panthro, struck down by the disease, becomes so desperate for relief that he asks Lion-O to take his life-force using a rarely used (and non-canonical) power possessed by the Eye of Thundera. (According to the story, this power may be used if a Thundercat is about to suffer a painful and protracted death.) However, a cure for the disease is obtained just in time to prevent Lion-O from having to resort to such desperate measures.
- In Elements of Harm, each of the Mane Six becomes an "Element" of a different aspect of warfare; Fluttershy, of all ponies, is the Element of the Mercy Kill, "quieting those in agony and making sure they stay down."
- In Child of the Storm, during HYDRA's assault on the Ministry of Magic, the Winter Soldier kills Arthur Weasley via Neck Snap in order to spare him being captured and tortured by HYDRA, or worse, handed over to Gravemoss. It's rather deconstructed, since even though killing him instantaneously was much kinder than anything HYDRA or Gravemoss would have done (in the sequel, Alison Carter, a woman who's been a spy and involved with the supernatural pretty much all her life, mentions that Gravemoss took a Fate Worse than Death to new depths), the fact is that he's still dead, which becomes rather awkward once the Weasleys have to interact with Bucky Barnes on a regular basis, even if they don't know at first that Bucky was the Soldier.
- Code Geass Megiddo: After killing his father to save the life of his best friend, only for said best friend, years later, to start a revolution in his country, culminating in not only the death of said country but also the death of the woman he loved and the tarnishing of her good name, and then betraying said now-former-best friend to the father he hated, having his memories wiped, and then having to play the part of best friend with him, one really can't blame Suzaku Kururugi for going full-throttle with the Sanity Slippage. It's for this reason that numerous characters state that if Lelouch truly does still care for Suzaku (which he does), this is the kindest thing he can do for him. Both Lelouch and Todoh acknowledge this, but state that if there's still the slightest possibility it can happen, they will both try to save Suzaku from himself, and even make pact over it.
- In the Magical Girl Crisis Crossover Shattered Skies: The Morning Lights, Alph is effectively euthanized by her master, Fate, after succumbing to the effects of a Hate Plague which destroyed her sanity and rendered her feral.
- In Apartment Gensokyo, Satori contemplates doing this to a severely injured and dying Koishi by overdosing her with pills but feels horrible for having the idea, so she stops, instead facing the idea of the latter being in pain. This is first serious moment in story.Satori: Should I let her suffer or should I take her life as an act of mercy?
- RWBY: Scars: In chapter 53, Pyrrha mercy kills an injured man who asks her to. He was the sole survivor of raiders attacking his village but had been crushed by a piece of ceiling. The scene serves to accentuate Pyrrha's Innocence Lost.
Mercy Kill / Fan Works