Villains are evil. They kick dogs instead of petting them. What if they started petting one dog in particular, and thereby showed some kindness, sympathy, etc. other qualifies not part of their villainous persona? That dog is the villain's morality pet.
These can be used when a villain becomes popular enough that the fandom becomes sympathetic to them. Thus, the author(s) want to use them more often and in more situations. However, meshing them into the main cast can be dangerous and disappointing if it leads to a Redemption Demotion. Some heroes wouldn't be quick to accept them, either. After all, they are villains.
One method of doing this is presenting another character to befriend them. Ideally, this should be someone who could pose no threat or even be demanding, and depending on how the plot goes, the recovering villain becomes fond of this other character and may draw stability from their presence. The Morality Pet may even be somewhat pathetic (and will be told so), but has often gone through some anguish to which the recovering villain can relate secretly, or reminds the villain of someone they lost long ago. They're usually upbeat, though they might go a little overboard sometimes. If handled poorly, they might become a Satellite Character for the former villain.
This also makes for a convenient excuse to help the heroes if needed; an ex-villain can simply claim to have their own "selfish reasons" and save face. Anyone messing with the Morality Pet can expect swift retribution from the ex-villain or antihero in question. If relationship with the morality pet is familial in nature, then Mama Bear, Papa Wolf or Big Brother Instinct (as appropriate) is involved. Sometimes Violently Protective Girlfriend or its male inverse if the morality pet is a love interest.
They are a living and recurring incarnation of Pet the Dog, i.e. something to placate the audience regarding the hero's tolerance of the amoral character, while focusing on the true villains. (Unless they Kick the Morality Pet, that is, which leads their character arc in a different direction.)
This isn't just for villains, either. Despite sidekicks being less popular in comic books than they were originally, some writers pair them with Anti Heroes in an effort to humanize them.
Not to be confused with a magic-user's familiar, the creature type of which often reveals the kind of person who owns it, though if the magic-user is fond of the familiar and treats it well, it could very well be a Morality Pet.
If the Morality Pet dies or disappears and this causes the villain/anti-hero to revert back to their old ways, the Morality Pet was acting more like a Morality Chain, a similar trope often confused with this one. The difference between the two is subtle: A Morality Pet is a character who redeems a villain. The villain's affection for the pet starts them down the path of good, and even should the pet get hurt the villain will most likely behave as a hero (or anti-hero) in seeking their revenge or protecting the pet. By contrast, the Morality Chain keeps an otherwise anti-heroic character (such as a Sociopathic Hero) from going full villain. The loss of the chain would spell doom for any involved party, and likely anyone nearby as well. In a nutshell, a Morality Pet turns a bad guy good, a Morality Chain stops a good guy from turning bad. That said, the two tropes can certainly overlap, if the character redeems a villain and then also helps keep them from slipping back to evil, they are both a Morality Pet and a Morality Chain.
Or to put it another way: The Morality Pet is a catalyst for a HeelFace Turn, while the Morality Chain is an inhibitor of a FaceHeel Turn. In this sense, the two are actually Opposite Tropes despite their close similarities.
Compare Predator Turned Protector, where their "pet" is the thing they're supposed to prey upon, and they act as full-blown protector rather than simply caring for/petting them.
Parent trope of Little Brother Is Watching.
- Anime and Manga
- Comic Books
- Fan Works
- Live-Action TV
- Video Games
- Web Comics
- Western Animation
- In The Elysium Project, Shay acts as this towards Mirage after their time together at Highmore Academy.
- The Book of Life:
- General Posada really does love his daughter Maria. And was distraught when it looked like she died.
- La Muerte is the sole being in the world that Xibalba respects and shows his soft side to. He is literally putty in her hands. Word of God even stated that La Muerte knows she's the only one who can change him.
- In Care Bears Movie II: A New Generation, Dark Heart manipulates a girl named Christy into helping him, but develops affection for her after she saves him from drowning. After accidentally harming her, his remorse is enough to not only help save her, but also turn him human.
- Despicable Me: Margo, Edith and Agnes for Gru.
- Epic: Mandrake, for his whole Evil Overlord shtick, really does care about his son.
- Anna in earlier drafts of Frozen was this to a villainous version of Elsa, who was going to freeze the country and Anna's heart on purpose, and at the end Anna changed her mind.
- Tip to Oh in Home. While the alien wasn't evil or even straight up jerk (or a Jerk with a Heart of Gold), he didn't know how to show any empathy towards other species, besides his own. Spending time with Tip allows Oh to learn.
- In Tangled, Rapunzel becomes this for Flynn Rider. While he's not an evil guy, he still starts off showing very little concern for his cohorts (he abandons his previous two partners in crime to be arrested and, likely, executed). When he ends up dragging Rapunzel into dangerous situations though, he does whatever he can to take care of her, and ends up falling in love and dying to set her free from Mother Gothel.
- In Treasure Planet, Long John Silver has a literal Morality Pet called Morph, a cute bloblike alien that apparently represents his conscience. One could argue that Jim Hawkins himself is another Morality Pet for Silver.
- The Blind Side: SJ for Michael.
- Minilla, or Minya, is this for Godzilla in the Showa series. And especially in Final Wars, when Godzilla ultimately decides to spare the humans simply because Minilla asked him to.
- In Guardians of the Galaxy, Peter Quill is this to adoptive father and amoral Space Pirate Yondu Udonta. Several Ravagers note that Yondu immediately becomes "soft" when Peter's involved and even refused to hand Peter over to his birth father, Ego the Living Planet. Yondu's love for Peter is pretty much his only redeeming quality, and the one thing he does selflessly is to sacrifice his life to save Peter from suffocating in space.
- How the Grinch Stole Christmas! has Max be a literal one. Although he participates in his master's evil deeds, he makes the Grinch save Cindy from the machine in the Post Office. He even has his own Christmas party while the Grinch is down in Whoville... until his master interrupts him and throws him out.
- The Hunger Games: Prim, for Katniss and Buttercup; she is one of few people they show any kindness to.
- Harley, the Tennessee boy who helps Iron Man repair and recharge his armour, in Iron Man 3 is this to Tony Stark.
- His brother and mother are this for the protagonist of Little Odessa.
- Maleficent has a major one in Princess Aurora, who is wholly responsible for her Heel-Face Turn in the later half of the movie, and a minor one in her servant Diaval, who, for all his undying loyalty to her, is a genuinely kind man(/raven) and has no qualms in calling her out on her cruel behavior.
- Pita for Creasey in Man on Fire. When Pita gets kidnapped, all hell breaks loose.
- Non-Stop: Were it not for Becca, a little girl who's on her first flight and rather scared of it, we would hardly see Marks acting like an actual human being as he helps her cope with her fear.
- Mass murderer Riddick managed to find a few morality pets in Pitch Black, Fry, Jack, and Imam. Of course, Fry died at the end of Pitch Black, and Jack (Kyra) and Imam died at the end of The Chronicles of Riddick, leaving Riddick with no more morality pets, and a whole empire of necromongers at his command! Be afraid. Be very afraid.
- Predators: Unlike the rest of the cast, Isabelle is clearly a tough-minded but fundamentally moral person. So the fact that she persistently tags along with Royce — and trusts him despite his erratic loyalties — gives the strong indication to the audience that there may a decent person somewhere under Royce's mercenary exterior, as does his behavior toward her.
- In Repo! The Genetic Opera, Marni acted as this for Nathan. When she died, the role was fortunately taken over by Shilo, who in turn became Nathan's Morality Chain.
- Chewbacca is pretty much Han Solo's Morality Pet. If he weren't so good at guilting his buddy, the Star Wars trilogy would have been over after one movie.
- Ira, who plays The Chick in a Five-Man Band, for Retired Monster Charlie in Suicide Kings.
- Subverted in Sweeney Todd: The Demon Barber of Fleet Street. Mrs. Lovett seems to have a soft spot for Toby and treats him as a son, but when he confides in her he suspects Sweeney Todd is up to something awful, she locks him in the basement and plans to have Todd kill him later.
- Maybe played straighter with Sweeney and Anthony. He's a non-threatening, innocent young character, whose puppy love for Johanna might reflect the young Sweeney's for Lucy. Subverted by the fact that is hinted at in the movie and openly stated in the musical: Sweeney's plan to get Johanna back involves murdering Anthony. Johanna may be Sweeney's real morality pet, but given that he nearly kills her as well by accident, being Sweeney's morality pet is not the best way to stay alive
- Barnabas was this to Saul/Paul when the other disciples questioned Saul's HeelFace Turn. See Acts 9.
- Jake "The Snake" Roberts, had Damien, his favorite of the many snakes he owns. Jake was never shown as anything but kind to Damien. In 1991, Earthquake squashed Damien. The feud against Quake was Jake's last as a face (he shortly thereafter had a FaceHeel Turn when he interrupted Randy "Macho Man" Savage and Elizabeth's wedding at SummerSlam 91, and sicced a cobra on him), and in a bit of Fridge Brilliance, one can look to Damien's squashing as his Start of Darkness.
- X Pac was briefly Kane's morality pet in the late 90s.
- In WWE, long-running Foreign Wrestling Heel William Regal was assigned by Eric Bischoff to baby-sit and team with his "special" nephew Eugene, a mentally-challenged man who was, despite his handicap, a capable wrestler. Regal quickly grew fond of Eugene, to the point where Triple H's cold, cynical manipulation of Eugene served as a catalyst for a rare HeelFace Turn for Regal.
- El Generico/Sami Zayn is Kevin Steen/Kevin Owens' in both Ring of Honor and WWE NXT... until his inevitable Face-Heel Turns in both promotions, of course. Since this is Sami, Kevin is, of course, Easily Forgiven after this happens.
- When WWE wants to put Alberto Del Rio through a HeelFace Turn, their formula is simple — have a heel assault his loyal manservant, Ricardo Rodriguez, and have Del Rio make with the Roaring Rampage of Revenge against the jerk who did it.
- Archangel Dominic in In Nomine is often depicted as an insane Knight Templar. One person's rather popular fanon solution to this was to give him a kitten to soften his image. This more or less worked for a large portion of the fandom.
- In Xantcha serves /Magic: The Gathering, Xantcha serves as Urza's anchor to morality and to sanity.
- Subverted in Children of the Night, a supplement for Vampire: The Masquerade. In it is a character profile of Velya the Vivisectionist, who fell in love with a 10-year old girl and made her into a vampire. The source of his infatuation with her was her blatant sociopathy, and willingness to manipulate her family into insanity and murder. But that's not the worst part. Even though she was as evil as they came, Elaine Cassidy wasn't mentally equipped to handle vampiric life beside one of the most cold and calculating inhumans in the world, and quickly went batshit insane, ultimately falling to the Beast during the 1950s. Velya's response to his "wife's" degeneration was to graft her body into his torso in order to keep her out of trouble until such time as he could find a cure. Worse still, not only have his efforts been completely in vain, but the connection between the two allows Elaine's Beast to influence Velya, gradually driving him insane.
- Archie, from 13 is actually an aversion of this. Archie uses the fact that he is terminally ill to manipulate everyone around him to get him what he wants.
- The eponymous character in Verdi's opera Rigoletto will simply be a small-minded, vengeful court jester, if not for his daughter Gilda.
- In William Shakespeare's Titus Andronicus, the otherwise cosmically evil Aaron goes to great lengths to protect his baby son/morality pet.
- Tsugumi of Ever17 was probably coming off a little too strong on the jerkass and a little weak on the Broken Bird. Plus they needed a way to suddenly make her get along better with Takeshi, so they introduced Chami the Djungarian Hamster. He's named Chami because he's charming.
- H-Game Gibo — Stepmother's Sin has the main charactter, Yusuke, doing pretty much everything he can to get into his stepmother's pants. However, he also has a stepsister, Shiina. In order to get the better endings (here defined as ones where you don't turn into a total bastard), you need to treat Shiina well, making her into one of these. Even when he's being a dick, Yusuke still refers to Shiina in kind terms.
- Not that Dr. Irie from Higurashi: When They Cry was a villain, but Satako Houjou was an influence in changing some of his priorities.
- Maria from Umineko: When They Cry acts as the pet for Beatrice.
- The entire Crew act as this to Nights to some degree in AJCO — her genuine love for them is her most redeeming feature and is what sets her apart from A_J, who really couldn't care less about her employees. Within the Crew itself, Blue acts as one to Krauzer.
- At no point in his rampages has Christian Brutal Sniper ever killed the RED Spy.
- ED-E plays this role to The Courier in Courier's Mind: Rise of New Vegas. The Courier can be quite a Jerk Ass (and who wouldn't be with the kind of life he's leading?), but will typically do the right thing if ED-E bugs him about it.
- Penny and Moist in Dr. Horrible's Sing-Along Blog definitely acts as morality pets.
- Moist manages to invert this in one scene, where his suggestions for evil acts are too overboard for Dr. Horrible.
- Dreamscape: Dylan, and to a lesser extent Aseir, are the only ones Jenna will show any sort of niceness to, and even then, its more akin to a Tsundere.
- DSBT InsaniT: Averted with Spoon towards Dave. Even though Dave spilled out his insecurites to Spoon, he has no issues with abusing him.
- Spiro of the Fellowship of The Questport Chronicles pulls a HeelFace Turn and is banished from the demon homeland after refusing to kill a Demon Bunny.
- In Noob:
- The relationship between Gaea and Golgotha is closer to a perpetual Licked by the Dog situation. Gaea combines Dirty Coward, Manipulative Bastard and The Scrooge, yet she and Gologotha seem to have never stopped being Childhood Friends and Golgotha not only actively seeks her company, but has quite a Big Sister Instinct towards her.
- A straighter but downplayed example so far only revealed in the webseries storyline is Judge Dead in regards to Tenshirock. Tenshirock was an Anti-Villain from the start, but the reveal of the relationship changes Tenshirock from some guy who has nothing better to do with his free time than messing up a MMORPG in an attempt to have people stop playing it to a father trying to win back the affection of a son that had started to hate him for reasons unknown to him.
- SCP Foundation:
- SCP-085, who acts as this for the entire foundation.
- SCP-053 acts as one for SCP-682 as she is the only being that 682 hasn't killed and actually protected her from the personnel who went in to separate them.
- Danya, Survival of the Fittest's Big Bad, is occasionally revealed to take time off from his commitments running the Act (including making the announcements) and going home to see his family. The obvious love and affection he has for his wife, young daughter and grown-up son serve to humanise him somewhat. Most members, however, still loathe him. They also fully support his activities, giving him even more motivation to act like a monster.
- In Thomas Sanders' Sanders Sides videos, Patton is this to... everyone. At the start, he's the only person Virgil will admit to liking, Logan will try to curb his usual haughtiness for Patton's sake, and even Roman will try to be more considerate with him.