The Alice Network: Eve is a war veteran who went through hell and lost many of her friends. And that's just part of what makes her past so awful...
In All for the Game, the Foxes tend to have these. The team is set up as something of a halfway house to give promising athletes second chances.
Burke from Andrew Vachss' books. Born to a mother (strongly implied to be a teen prostitute) who promptly abandoned him, brought up through a variety of foster and juvenile homes, and experiencing the worst that humanity has to offer is a very succinct description of his past.
Tobias. His natural father had to leave, and he was given a fake father, who then left himself. His mother was in an accident and didn't even remember him, besides being blind. He was bounced among aunts and uncles who didn't really care about him and became a bully magnet.
Marco. The disappearance of his mother and the subsequent split of his family caused him to become more cynical and, in effect, more ruthless and pragmatic and less attached to romantic, idealistic principles. To make matters worse, one of the Big Bads has possessed his mother.
While the Aunt Dimity series is generally upbeat, many characters have had brushes with insanity, tragic accidents, serious diseases, major injuries, even war and murder. In some cases, coping with the fallout occurs over an extended period (often carrying over from one book to the next). The fates of other, more minor characters are addressed in the epilogue that closes each novel; they typically go about rebuilding their lives, and are usually better off after all is revealed.
Noir, from the web serial Barkwire, a dog who "has buried more secrets than bones."
Colin Whisterfield, in Alan Garner's novel Boneland. It is progressively revealed throughout the book that before he was thirteen, he:
was possibly abducted and sexually abused by a man and a woman;
lost his parents to a plane crash;
lost his twin sister in mysterious circumstances - she went horse-riding by night, and only the horse was found; it is assumed she was thrown in the waters of a lake and drowned;
was struck by lightning while alone in the hills, suffering brain damage that went undetected until an MRI scan in later adulthood.
Trini in A Brother's Price is an Ice Queen, and eventually revealed to have been tortured and raped by her late husband. Who convinced her elder sister that it was entirely Trini's fault. Her sister in turn convinced Trini of this before their mother came home. Fortunately, the husband, Keifer, died in an explosion not long afterwards ... along with several of Trini's sisters. Which gives all the remaining sisters a dark and troubled past. The only ones who are not really affected by it are the young ones who were babies or toddlers at the time.
Wang Sau-leyan in Chung Kuo. He was ugly, fat, clumsy, and treated as a poor sequel to his brothers while he grew up. This is not presented as an excuse for his behavior, but it helps explain it.
Mallory. She has no memories of before she was six and came to Cloak, despite telepathy efforts to get past her trauma; she has been told that she killed her parents with her powers. Actually, Cloak murdered them and erased her memories.
Kirbie and Kyle are less troubled, because of the Parental Substitutes they had in the Rangers. Nevertheless, when Kirbie recounts how their parents had brought them to the city on a vacation, left them in a park on the pretense of getting ice cream, and never returned, it was still clearly painful for her.
A large part of Damnatio Memoriae is the reader waiting to find out what happened in Enim's past that had caused him to become so withdrawn and troubled. It's then revealed that his mother jumped off a bridge, survived but is now in a vegetative state being kept alive by his uncle, and Enim could have stopped her. Oh, and she had schizophrenia and Enim most likely has it, too.
Gillian Flynn's Dark Places has Libby Day, who saw her mom and two sisters murdered when she was seven years old. She then testified against her older brother, Ben, who got life in prison. Then she grew up being bounced around distant relatives and foster homes, eventually alienated her aunt Diane (the only close family she had left), never got a job or got over the murders, and "grew into a deeply unloveable adult."
"Draw a picture of my soul and it would be a scribble with fangs."
In Sarah A. Hoyt's Darkship Thieves, Kit's wife died, and it looks like he murdered her, and he refuses to clear his name out of, it turns out, fear that other dark elements of his past will turn up.
Sajag from Dragon Queen killed a guy and then had to go into exile away from his family.
Harry in The Dresden Files. Never knew his mother, his dad died when he was a kid, bullied at an orphanage, adopted by an abusive Evil Mentor who tried to turn him to The Dark Side, had to kill him in self-defense, arrested by the White Council, barely escaped the death penalty for violating the Laws of Magic, and is still under the Doom of Damocles and being stalked by an Inspector Javert at the beginning of the series. None of this is what makes him a woobie; he is one because, taking into account the things that happen to him during the actual series, his backstory isn't depressing so much as it's "a very small taste of what's to come.''
In Devon Monk's Dead Iron, Cedar's brother Wil dragged him west after the loss of his wife and children. Then they went on the wrong land and were cursed into werewolf form. Cedar came to find himself at the end of a bloody trail, and backtracked to find his brother's wolf corpse, its throat torn out by himself.
In Robin Jarvis' Deptford Mice trilogy, Thomas Triton is haunted by feelings of guilt for being responsible for the death of his friend Woodget Pipple. In the prequel book Thomas, which describes the incident in detail, it is revealed that the villainous Ma Skillet put him into a trance, causing him to throw Woodget (who could not swim) into the ocean. When he awoke from the trance, he realised what he had done and was filled with remorse. However, unbeknownst to him, Woodget was rescued by a siren whose song gave him amnesia. He was brought to the City of Hara in India and became their new sadhu.
As a child, Karyl saw his immediate family being eaten alive by a wild dinosaur. As if that wasn't traumatic enough, soon afterwards his aunt kicked him out of the country to take over his family lands, leaving hism with nothing but a pair of trousers and his pet allosaurus Shiraa. He managed to climb out of it, though - he spent years serving as a mercenary on Shiraa's back until he amassed an army of his own and took his country back.
Falk's father is said to have been extremely abusive, to the point that Falk still has nightmares about him and has o tell himself that the man can't hurt him anymore. He ended up pushing his father off the stairs, killing him, on orders of his mother, who's equally abusive, although in a different way.
Vulpie in A Fox Tail has a particularly dark one, almost to the point of parody, beaten and shot by his birth father at 5, raped by a priest at 12, beaten by another foster parent for being gay... A psychologist strongly believes that it's his reason for hacking the known universe, but Polar helps him grow out of it.
Séraphine Francq (Fiancée du Vent): lost her mother at a young age, her father died from the experiment that gave her her powers, was gang-raped by schoolmates, and consequently beat them up so hard that one of them is stuck in a wheelchair for life, giving her remorse...
Both Greg and Emma from the novel Fort Hope have troubled pasts. They come to find out their dark and troubled pasts are linked. Of course, in that book, almost everyone is related somehow.
Nikita from The Girl from the Miracles District has spent her entire life running with her mother away from her insane father, all while dear old mom had her assist with assassinations and training her to be a killer - on pain of not getting any food if she failed a task. And when Nikita's father got to her, he kidnapped her, tortured and cut off two of her fingers, just because.
Phyllis Hatherley's past is not only mysterious but also shady in The Ghost Writer. One of story's major plot points is her son's attempts to discover her past right from her childhood.
The Marquess from The Girl Who Circumnavigated Fairyland in a Ship of her Own Making has a very troubled past. She stumbled into Fairyland when she was 12, lived there for many years, fell in love, became a heroine and queen, and became pregnant. Then she was snatched back into the human world, stuck in a 12 year old's body and with her alcoholic and abusive father, no husband, no child, and no Fairyland.
Both main characters of Gives Light. Skylar had his mother murdered in front of him when he was five. Her murderer realized he was in the room and slashed his throat. Skylar didn't die, but now he's irreversibly mute. To top this all off, his one dream in life is to be a singer. And then you have Rafael, son of said serial killer. Everyone equates him with his father and he has no friends. Until he meets Skylar.
Kieran Trevarde of The God Eaters has a dead mother, some degree of rape and child prostitution, as well as drug addiction in his past, and a dead lover on top of all that at the outset of the novel.
Harry had both parents murdered before his eyes at age one, nine years living with abusive guardians, being bullied at school by his cousin and his cousin's friends, a dead godfather, a dead mentor, the most evil person in his world has a connection to him, a life and death battle every year, and sometimes his friends turn their backs on him.
Neville Longbottom also deserves a mention. Lives with his grandma because his parents were tortured into insanity by Death Eaters and feels that he can never live up to them and has no self confidence at all. He also thought for a long time that he was a squib and only discovered his magical ability by being dropped out of a window.
Sirius Black, who had (let's count!): 1) a dead best friend, 2) a dead brother, 3) abandoned (disowned) by parents, 4) spent 12 years in prison for a crime he didn't commit (for bonus points, this jail employs Dementors as wardens) , 5) been betrayed by former True Companion.
In Heart's Blood, Anluans entire family history, all the way back to his great-grandfather, Nechtan, who had an evil summoning spell go VERY wrong.
Caitrins isnt exactly bright and cheery either. Her fathers dead, her sister married and left her, and a distant relative took over the house and allowed her son to beat Caitrin when he felt like it.
The members of the host are all souls from Purgatory. Some of them seem to have particularly violent pasts.
In Heart of Steel, both Alistair and Julia have their own traumatic pasts, over which they ultimately bond:
Alistair—back before he was Alistair—was in a car accident that left him badly mutilated and his girlfriend in a coma. Because he was a robotic genius even then, he rebuilt himself out of metal parts over the course of five years, only to discover when he went to visit his girlfriend that her parents had had to take her off life support the week before. Cue psychotic break.
Julia was attacked at the hospital where she worked and nearly killed by a deranged junkie looking for drugs. The incident left her with PTSD, unable to go back to work due to panic attacks.
Hostile Takeover (Swann): Klaus and Jonah Dacham were raised by an abusive mother, who often threatened them with their absent and nameless father. They joined the secret police to escape her, and were groomed to commit atrocies, peaking in Jonah's massacre of 35,000 rebels and innocent bystanders on Perdition.
Oreg from the Hurog duology could be the poster child for this trope. He is something like a ghost, but does have a body, which can feel pain. He has also been a slave to generations of men from a family whose members are known to be frequently violent or insane, or both. Think about the implications. His current owner Ward also comments that Oreg is "a pretty boy", and he knows what this would have meant to some of his more unsavory ancestors. He also notices that Oreg experiences flashbacks, fueled by magic to be more realistic than the mundane version. Of course, Ward had no happy childhood either, he eventually had to pretend to suffer from braindamage after a beating, as his father would have killed him if he had presented a threat to his father's keeping the power. Ward's younger sister didn't have a happy childhood either, and he helped his brother escape after said brother tried to commit suicide because he couldn't bear it. Their mother is The Ophelia. Many other people in the story don't have happier pasts, but if there were a competition, Oreg would win, as his dark past is longer than any of the others'. And more mysterious.
Eve was abandoned by her mother, raped by her father (who impregnated her mother with the sole intention of selling her to child molesters), killed him in self-defense, and then had to handle at least one abusive foster parent as she grew up in the system.
Roarke was regularly beaten up by his father and non-biological mother, had to steal for his father, and even though Summerset took him in, they lost Marlena, Summerset's daughter, to a group of rapists.
Dr. Mira watched her parents divorce, her mother remarry, and was sexually abused by her stepfather to the point of being Driven to Suicide (fortunately, she survived). Boy, these three had it rough, didn't they?
The Infernal Devices: Jem Carstairs. A demon who had a grudge against his mother tortured him in front of his parents, injecting him over and over with a drug that made him hallucinate vividly.
James Bond: 007's parents were killed during a climbing accident in the French Alps when he was eleven.
Mr. Rochester was betrayed by his greedy father and brother to marry a woman they knew was insane just to get her money, and all the man ever wanted was to find someone to love.
Jane had one, too. She was orphaned, put into an unloving and abusive home, and sent to an unsanitary boarding school that could barely feed its students. The first friend that she made there died shortly after she arrived, as did most of the other students in a typhoid epidemic.
Eric's initially low self-confidence and self-esteem is due to his past but it is mild compared to some of the people he meets.
Kallen Selios is a survivor of the Siduban Chaos Explosion and her parents were not. She was adopted by her mom's business partner because her remaining blood family was afraid of her mutation. Since then she has faced discrimination for being a demon and a "labrat".
Zettai's parents were abusive, and after they died, she was homeless and vagrant. She traveled constantly to evade Ceiha's secret police because she was a courier in the magical black market. Then they eventually caught her and bad things happened to her behind bars. When Nolien shines an Illumination Orb over her at night, her automatic response is to shout "I'm innocent! Please don't arrest me!"
Fisk from the Knight and Rogue Series. He took up crime to support help support his sisters after they lost both parents to disease. When his oldest sister marries someone who could take care of them, he decided Fisk alone couldn't stay, becuase he didn't want to be associated with a criminal. And that's ignoring everything involving Jack Bannister.
Legacy of the Dragokin: All of Kthonian Knights have one; the three girls were kidnapped and raped by truly evil men and the guy had his hands cut off and left for dead for deserting the Leondian army. All of them function as a Freudian Excuse except for the last one. The only thing his past does is make him angst about how he can no longer truly embrace his precious little sister.
In A Legacy Of Light, main character Tutankhamun's parents, grandmother, and five of his sisters died before he'd turned nine, and before he was nineteen, he and his wife had lost two infant daughters.
Most of the main characters from Loyal Enemies haven't lived a life of roses so far:
Veres was a skilled, talented mage on the verge of handing in his thesis and becoming an archmage. Then the love of his life was suspected of being a crazy necromancer and he refused to be interrogated, believing her to be innocent. He was tortured for information for days, left the prison as a functional cripple, was banished from the capital, had all of his possessions confiscated and his career thus ruined. To top it off, his lover Tairinn was killed by a werewolf a week later. If not for his friend Gloom, he'd probably have died right there and then. The worst part? Tairinn wasn't innocent at all and never loved him, faking her own death.
Werewolf Shelena has her share of bad memories. Among others, her first child was lynched, she had to leave a man she loved behind because he despised the wolf side of her and wanted her to kill it with an elixir, and she was once captured by an Ax-Crazy monster hunter and tortured for days before being left to die. That's not mentioning all the times she had to leave everything behind because people found out she's a werewolf.
Rest, Veres' apprentice, was thrown out of his home and by several masters he was apprenticed with, often for no good reason other than that they didn't want to feed another mouth anymore. Veres found him on the verge of dying from falling into the lake in the middle of winter beneath a flight of stairs, while his drunk father was about to beat him for falling in.
Virra is a seven-year-old half-elf girl who, due to her clan who all have the killing touch, is being shunned by both elves and humans. She lost her family to vicious bird-reptile monsters and has been told so often that she's a monster and worth nothing that she's started to believe it.
Francis Crawford of Lymond in Dorothy Dunnett's Lymond Chronicles. He's got almost everything: rejection by his father, didn't fit in as a child, betrayed by his early—perhaps first—lover, framed as a traitor, physical and perhaps sexual abuse as a galley prisoner, self-hatred because he blames himself for his sister's death, and pretty much everyone he cares about dies as a result of knowing him.
Vin from Mistborn. Born the daughter of a skaa (peasant) woman and an Imperial nobleman (a death sentence from the get-go), her earliest memory is of her insane mother killing her little sister and performing Hemalurgy to transfer some of her soul to Vin, before being rescued by her older half-brother. Said half-brother genuinely cares about Vin, but he's a cynical, abusive Jerkass who hammers into her head the idea that she can't trust anyone because everybody is selfish and manipulative. They spend the next several years working as petty thieves on the lowest rung of society, until the half-brother runs out on her, though it turns out that he was actually captured and executed, leaving Vin without a protector in a den of scum. Of course, from there, she gets recruited by La Résistance, finds out that she's an Extraordinarily Empowered Girl, and takes a level in badass, but still. Is it any wonder the poor girl spends most of the trilogy wrestling with crippling paranoia?
Jace Wayland from The Mortal Instruments, saw his father, Michael Wayland, murdered in a pool of his own blood. That was staged, of course. And Michael Wayland was never his father.
Kvothe from The Name of the Wind had his entire troupe die, lived homeless for three years, got kicked out of the only place he felt he belonged after the death of his troupe...and that's just what we know so far.
Samantha Cataranes from The Nexus Series has a particularly unpleasant past. It is strongly implied during the first book that her experiences drove her to revile "Transhuman" technology and join the ERD as soon as she was old enough.
There are eight main characters in Of Fear and Faith and each one has experienced either a crappy, abuse-filled childhood or a life-altering, emotionally scarring tragedy. To put it in perspective, the character who lost his father when his hometown was destroyed probably has the least depressing backstory.
In the Nightfall (Series), Prince Vladimir's entire human family was killed as a result of a rebellion gone wrong. However, he never uses it as an excuse for his evilness and is unapologetic about what he has done to humanity.
Everyone in The Pale King, but Toni Ware especially. She spent her childhood in perpetual poverty as she and her sometimes-crazy mother drifted around the country. She also saw her mother murdered right in front of her.
Since all of the princesses of The Princess Series are based mostly on the Grimm Bros. version, they all have this, though some more than others.
In Morgan Ray Hess's Rainbow, both of the main leads had very tragic and traumatic childhoods.
In Rama II, Nicole failed to win a beauty pageant because of racism. After she won an Olympic medal in sprinting, she hooked up with the prince of France, who abandoned her when she became pregnant with her daughter. She had to move in with her father, who allowed her to raise Genevieve with him. Genevieve's parentage still haunts her public life, such as her questioning by Sabatini. Francesca was sexually adventurous as a youth, and some past experience has left her callous, to the extent that she uses everyone. Richard had a father who abused him and his mother, leading him to feel very isolated (and eventually near suicide); this was spurred by his father being unable to cope after he lost his job as an engineer, suffering a case of Intelligence Equals Isolation. Adultery from his girlfriend when in college pushed him over the edge, such that he hurt, and then also nearly killed himself. Other characters are not generally shown to have explicitly traumatic pasts, but Brown was the cause of one for his wife and former PhD student, Elaine (whose scientific results he stole), and cosmonaut Janos is implied to have had to suppress homosexuality and political involvement, form his youth, in order to join the astronaut academy.
In River of Teeth, Houndstooth used to be a hippo rancher, the most talented at breeding hippos in all of the United States. He'd worked for fifteen years to save up the money to buy his own ranch. It was burned down by Cal Hotchkiss who was working for Travers by that point and was eager to impress Adelia Reyes. Houndstooth had to watch dozens of his beloved hippos burn alive, which set him on a downwards spiral until he met Archie and decided to live his life for his sole remaining hippo Ruby.
Camille from Sharp Objects suffers from this. She grew up with a Disappeared Dad, an abusive mother, and an Ill Girl little sister who died when Camille was only thirteen. She also got gang-raped at thirteen by a group of football players. She's been a cutter since childhood, and shortly before the book starts the problem got so bad she checked herself into a psychiatric hospital. While there, she witnessed her roommate, who she had grown close to, kill herself. In the present day Camille is still a cutter, and a Broken Bird and The Alcoholic to boot from these experiences.
In The Sisterhood of the Traveling Pants, Bridget's mom committed suicide when she was a child. Her father and twin brother cope with this loss in unhealthy ways, and much of Bridget's flighty and impulsive nature comes from leftover trauma she has surrounding her mother.
Kaz came to Ketterdam at the age of nine. Almost immediately, his brother is tricked into signing away all of their money, they become homeless, a plague kills his brother, he is left for dead on a barge full of dead bodies, and he returns to shore using his brother's corpse as a float. No wonder he became the Bastard of the Barrel.
Inej was just an acrobat with her family before being kidnapped by traffickers and brought to Ketterdam, bought, placed in a "pleasure house", and forced to have sex with horrible men before Kaz purchased her indenture and made her a spy instead.
Jesper's Grisha mother died because she pushed herself too far, his father encouraged him to stop using his powers (likely causing mental illness), and he ended up with a gambling addiction, working as a sharpshooter for a gang, after dropping out of university.
Wylan was absolutely tormented by his wealthy father due to his dyslexia, and ended up nearly being murdered by men his father hired before making it into the Barrel and being taken under the wing of the Dregs. To top it all off, his beloved mother who he had been told was dead turned out not to be dead after all, but locked away in an insane asylum so his father could control her money and assets.
Matthias discovered that he had essentially been brainwashed by trusted adults and was imprisoned to fight in an arena, repeatedly.
Nina was captured by enemies and nearly killed for being a Grisha, before escaping thanks to a shipwreck, rescuing one of said enemies, falling in love with him, and being forced to label him a slaver and get him arrested in order to save his life. Oh yeah, and this tops off being trained at a young age and experiencing a civil war as a young child.
Sandor Clegane killed an innocent peasant boy and laughed about it, however the fandom forgave him as soon as he confided that his older brother Gregor had burnt his face as a child.
Jez from the Spaceforce series, a space vampire whose entire race was almost totally wiped out in a genocidal uprising by their own 'bloodservants' when she was a teenager. The remnants were exiled from their homeworld, and now face fear-based prejudice in a supposedly liberal galactic Union.
The Spirit Thief: While all three main characters have some degree of this going on, Nico takes the cake. As a young child, she was kidnapped by slavers and sold to the Dead Mountain cult, where she grew to be Master's worshipper by the way of Stockholm Syndrome. She was eventually implanted with a demonseed and sent out to murder everything - until the League of Storms beat her within an inch of her life and the Master abandoned her, took his powers away and told her she's a failure and should die. If it wasn't for Josef appearing at a fortunate moment, she absolutely would have.
Xaverri's husband and children were killed by the Empire, inspiring her vendetta against them. She declines to go into details on what happened, saying recounting it might kill her.
Han's past also counts-he was a street urchin recruited by a criminal into working on his behalf as a beggar, con artist and thief. Before that, though details aren't revealed, it's implied that his parents were murdered and he wound up on the streets with his memories of them erased for an unknown reason.
Dash Rendar's family, it turns out, were once wealthy Corellian merchants, and he was in the Imperial Academy. Then his brother accidentally crashed into the Imperial Museum on Coruscant flying a ship, dying in the process (it had been sabotaged by Xizor, because they wouldn't sell their company to him). In revenge, the Emperor had Dash expelled and exiled his entire family from the Core while seizing all their property, ruining them. Since then he's been a smuggler. It's brought up by a Rebel to appeal for his help as he has good reason to despise the Empire, but Dash still doesn't join them full on.
Xizor, although the villain, also has one. After a deadly virus escaped from a lab in a city on his planet, the Empire destroyed everything within a hundred mile radius to contain it. This resulted in the deaths of his parents, siblings and two uncles, along with over a hundred thousand other people. It's implied he really did love them, and wants revenge against Vader (who ordered the virus project) due to this.
In Andre Norton's Storm Over Warlock, Shann Lantee was a Street Urchin. The only affection he got during that time was from a pet bird, that died in pain. He was at least once tortured with an Agony Beam by a bully. And he saw people under mind-control — a fact which he blurts out to Thorvald; that deeply embarrasses him, because it underscores how unlike the standard Survey team member's life his has been.
Lucky was abused by his previous owner, which caused him to become a stray dog.
Alpha was ostracized by his wolf pack due to being the offspring of a dog and a wolf. This led to a lot of bullying growing up.
Sweet was a neglected racing Greyhound who was abandoned after she became "too old".
Both Tailchaser and Roofshadow have similar pasts in Tailchaser's Song. They're both the Sole Survivors of their families. Tailchaser's mother and siblings mysteriously vanished several months ago when he was a kitten. Roofshadow's trauma is even worse. She came home to find everyone in her entire clan either vanished or savagely torn apart (including her favorite brother and Only Friend Snufflenose).
Tasakeru's primary characters, the Outcasts, are shining examples of this trope, it's pretty much a prerequisite for being one. One is a runaway Samurai suffering from Survivor Guilt, one was disowned by her family for being a mage, one grew up in poverty and had to steal to survive...
Most of the vampires from Twilight seem have dark and troubled last minutes of their human lives; the terrific pain of the transformative venom doesn't help matters.
In Wen Spencer's Ukiah Oregon series, Ukiah was abandoned in the woods to run with the wolves before that, Magic Boy was brutally murdered, eventually creating Ukiah and Atticus. Atticus Steele was another foundling. The foster parents who would have adopted him died in a car wreck and he was passed from foster home to foster home throughout his childhood. Max Bennett's wife disappeared mysteriously while he was on a speaking tour, only to turn up at the bottom of a lake from a car wreck.
Barbie, from Stephen King's Under the Dome, has a greatest failure in the time he allowed his military unit in Iraq to torture and kill a prisoner for no reason. He regrets this for the rest of his life, and his remorse thinking back on it is bad enough to get an Energy Being who sees him as an ant to show pity on him.
Villains by Necessity: It's revealed that Sam grew up in poverty with his mentall ill mother, the pair squatting inside an abandoned warehouse to survive. Then he walked in once to find that she'd been raped and beaten by a random drunk. He killed the man, with the building catching fire when the lamp fell over. After he escaped, the assassin's guild recruited him.
Bluestar's mother died when Bluestar was only an apprentice, and her father never really paid much attention to her and her sister. Her sister died as a young mother, and Bluestar felt guilty for her death because she'd convinced Snowfur to leave the camp for a little while. She had kits with a RiverClan cat (a forbidden relationship), but had to give them up in order to become deputy instead of Thistleclaw, and one died.
Crookedstar sustained a disfiguring injury as a kit. Because his shallow mother couldn't stand having such an ugly kit, she neglected him, favored his brother, and renamed him Crookedkit for his injury. After he rejected his Evil Mentor, she cursed him so that he would outlive everyone he ever loved, completely helpless to stop it.
Yellowfang, a medicine cat, had kits with the Clan leader (another forbidden relationship). Two of them died, and the one that lived became cruel and bloodthirsty, killing his own father and taking leadership, breaking the warrior code by stealing kits from other Clans, and even murdering kits from his own Clan and framing Yellowfang.
Iseult has ran away from home shortly after Corlant started taking unhealthy interest in her mother, and nearly died when she was discovered by a Carawen monk. She had to leave the monastery as well, and then almost died again before Safi saved her and they became Threadsisters. All the time, she had to manage the copious amounts of Fantastic Racism that all Nomatsi face - in the Dalmotti Empire, they're considered animals.
Aeduen apparently used to live in a Nomatsi settlement before something happened that made him terrified of fire, killed his mother and caused him to flee. He was found by a Carawen monk and joined the monastery, but was ostracized there for being a Bloodwitch. At some point later, his father roped him into his schemes and convinced him that Aeduan should accept being a demon other people see him as.
Cam grew up in a gang, and his brother wanted him to become another gangster. Adding to that, he's biologically a woman, and everyone in the Nines think that he's just pretending to be a boy for laughs. He joined the Navy to escape the life of crime, but it caught up with him anyway.