Origin Story

In comic book terminology, an origin story is an account or back-story revealing how a character or team gained their superpowers and/or the circumstances under which they became superheroes.

In order to keep their characters current, comic book companies, as well as cartoon companies, game companies, children's show companies, and toy companies, frequently rewrite the origins of their oldest characters. This goes from adding details that do not contradict earlier facts to a totally new origin which make it seem that it is an altogether different character.

"Origin story" or pourquoi story is also a term used in the study of myths. It can refer to narratives of how the world began, how creatures and plants came into existence, and why certain things in the cosmos have certain qualities.

Anime & Manga

 * Astro Boy - A robot created to replace his creator's son, who was killed in a car accident in the anime and by a robot in the film, and was equipped with weapons that he uses to fight crime.
 * Strider Hiryu - A brave assassin sent by the Striders to kill Grandmaster Meio.

Comic Books

 * Sophie Karamazout - Mr. Karamazout is the inventor, which he had no wife and even no children. So, he decided to have his own daughter. He mixes the ingredients to create a little girl using a mixture of sugar, spice, and everything nice. Then, Sophie Karamazout is born.
 * Captain America - He became a super soldier thanks to a serum that enable him to fight against HYDRA led by Red Skull. Later, while taking on the Red Skull during World War II, Captain America fell into the sea, where he was frozen until the present day where his fight against evil continues.
 * Thor - Thor was sent to Earth to live as mortal named Donald Blake without memories of godhood due to his father, Odin, wanted him to learned humility.
 * Batman - Bruce Wayne had parents murdered by one of the muggers when he was young while walking home from the movies with his parents,. This, and later discovered that Gotham has plagued by corrupt officials, inspired him to used his vast family fortune to become Batman and wage a one-man war on crime.
 * Spider-Man - Bitten by a radioactive spider, Peter Parker found himself bestowed with spider-based superpowers. He was motivated to fight crime by his uncle's death, which he blames on himself.
 * Superman - Born on the planet Krypton, infant Kal-El was sent to Earth before an explosion destroyed his home planet. His strong moral code motivated him to fight for justice.
 * Supergirl - Like her cousin Superman, she was born on the planet Krypton. Supergirl and her parents did survived from the destruction of her home planet when they were incased in Argo city which was protected by an indestructible dome. When Krypton blew up, Argo city blew off of the planet and floated into extra dimensional space. Then she was sent to Earth to become her cousin's female partner.
 * Wonder Woman - Diana, the princess and appointed champion of the Amazon warrior women, who left her homeland to battle injustice in the world of men.
 * Iron Man - American industrialist Tony Stark was captured by Communist Vietnamese military and forced to build weapons for them. Instead, he built powered armor to escape. He then uses his armors, which is more improved that the first one that he used to escaped, to fight crime.
 * Fantastic Four - Four astronauts (Reed Richards, Sue and Johnny Storm, and Ben Grimm) who were exposed to cosmic rays, which gave them superpowers.
 * The Flash - Barry Allen, a forensic police scientist, was struck by lightning and bathed in electrically-charged chemicals, connecting him to the Speed Force and giving him super-speed.
 * Incredible Hulk - Dr. Bruce Banner, belted by gamma rays after pushing a teenager named Rick Jones into the ditch near the test field, now turns into the super-strong Hulk whenever he gets angry.
 * Green Lantern - Test pilot Hal Jordan receives a power ring from the dying alien police officer, Abin Sur, and becomes a member of the Green Lantern Corps.
 * Judge Dredd - Awoken from his sleep with his clone Rico, Joseph Dredd witnesses nuclear war going on. They then split up. Rico becomes an evil-doer, Joseph becomes the toughest judge yet — Judge Dredd.
 * Sabrina Spellman - Hilda and Zelda Spellman mixes magic potions and ingredients to create an evil, wicked witch. Unfortunately, they accidentally got a wrong potion as an extra ingredient and then Sabrina Spellman is born.
 * Teenage Mutant Ninja Turtles - When a boy was walking, carrying his four turtles in a bowl of water, a toxic slime truck stood in his way. All four turtles and one of slime canisters the truck carries simultaneously fell into the sewers by accident when the child and the said truck passed by onto each other. In the sewers, the turtles met Splinter the rat whom recently lost his master Yoshi at hands of Oroku Saki where in that fateful day the canister that fell alongside the turtles shattered and resulting them and Splinter exposed by its mutagenic chemicals inside, mutating them into humanoid anthropomorphic version of themselves. Splinter would later adopted the mutated turtles, named them after important figures of Renaissance era and taught them ways of shinobi so they can ready to fight an evil that invaded New York in the form of the Shredder (whom none other than Oroki Saki himself) and other villains ranging from notorious criminals called Purple Dragons to hostile aliens.
 * Daredevil - He started a normal life as regular guy named Matt Murdock until was blinded by chemicals. After overcome his deteriorating vision with enhanced hearing, he devotes to fight crime as Daredevil.
 * The Punisher - His family was killed by mobsters, and Frank Castle devotes to fight crime in his own way as the Punisher.
 * Wolverine - After he got bone claws upon the awakening of his mutant powers, his claws fused with adamantium due to undergo Weapon X project, and he escapes the pool he was in, the very same pool which made his bones coated and reinforced by adamantium.
 * Ghost Rider - The origin story of those whom possesses the mantle of Ghost Rider mostly due to bonded themselves with the powerful demon Zarathos except for Robbie Keyes:
 * Johnny Blaze: He was a motorcycle stuntman whom possessed/bonded with a demon named Zarathos due to a deal that made with Mephisto, something that he later used to take on crime.
 * Robbie Reyes: Robbie Reyes become a new Ghost Rider whom, as discovered by Johnny Blaze, was the result of possession by the satanic ghost of his estranged uncle, Eli, which bestowing him powers that bot similar and equivalent with that of Zarathos'.
 * Arrow - Oliver Queen was a billionaire playboy who was shipwrecked on an island in the middle of the Pacific. Five years later he returns home on a quest to save his city.
 * Beast Boy - Beast Boy was once an ordinary human boy named Garfield Mac Logan whom having scientist parents inject him with reverse evolution serum to save his life from a deadly virus that led to his superhero career.
 * Raven (DC Comics): Born from a human mother Arella and demon father Trigon, Raven realized that her powers would be used by Trigon to destroy the world, she would do whatever it takes to stop Trigon includes join forces with a superhero team named Teen Titans, which also kickstarted her career as superheroine.

Films-Animated

 *  DreamWorks 
 * Turbo - Theo is a garden snail who dreams of becoming a racer. As he wanders onto a freeway to admire the traffic, he wishes he was fast on the first star (which is actually an airplane light). Suddenly, he gets into a freak accident when he gets sucked into the supercharger of a drag racer, fusing his DNA with nitrous oxide, resulting mutation that giving him super speed.
 * Puss in Boots - He was an orphaned cat, who befriended Humpty Alexander Dumpty at an orphanage. They both stole different types of beans in the search of the magic beans. After some time, Puss gave up stealing things. But, Humpty, unable to steal without the cat's help, tricked him into a bank robbery. From then on, Puss became a fugitive from law, searching a way to clear his name.

Films-Live-Action

 * RoboCop - Originally, Officer Alex Murphy is killed in the line of duty and brought back to life as a crime-fighting cyborg called RoboCop; in the remade film, he is horrifically wounded and rebuilt as a cyborg.
 * Godzilla - Godzilla was once a dinosaur who was later transformed into a giant monster by the nuclear test that damaged his original home.
 * For Legendary Pictures incarnation, Godzilla is one of known survivor of prehistoric amphibious reptile that feed of radiation whom prefers to avoid conflict with humanity but not above wiping out any lifeform whom threatened the balance of nature like M.U.T.O.s.
 * Machete - Machete was a man with an injured leg befriended by his priest brother.

Literature

 * Eloise - A snobbish little girl, Eloise, who is inside a large pink box, was sending to The Plaza Hotel in New York City. When they leave, after they put boxes in a top floor, the box is opened and Eloise crawling out.
 * Christopher Robin - In England, UK, Christopher Robin and his family are lived in a house. He had his room filled with stuffed animals (especially his teddy bear named Winnie the Pooh). While Christopher Robin reading a storybook, he notices it was a magical book. Christopher Robin is very happy as he jump through the pages of the storybook and magically transported to a magical world called "Hundred Acre Wood". He is based on the real life Christopher Robin Milne, (the son of author A.A. Milne).
 * Conan the Barbarian - Conan's family was killed in the films or turned to stone in the cartoon. He swears to destroy all evil within his land.
 * King Arthur - According to legend, when he was a boy, he pulled out a sword from a stone, thus becoming king.
 * Harry Potter - He is a wizard and his parents were killed by Voldemort, who left him with a scar due to him destined as the great power that can destroy Voldemort.

Live-Action TV

 * Power Rangers - They were five ordinary teenagers chosen by Zordon to become the world's colorful superpowered superteam, the Power Rangers. Upon Zordon demise, numerous people, includes his apprentice Gosei became supervisors of the new Power Rangers generations that would later carry the same duty that previous Power Rangers did in spite of how the said people either had Morphing Grid come for them of they found Morphing Grid themselves.
 * Dex the Masked Rider - Dex was given powers by his grandfather, the king of Edenoi, and is sent to our world to protect it from the advancing evil of Count Dregon. Dex was raised by a family, and learns to live as a human. With his companion Ferbus by his side, Dex is ever vigilant, ready to call on his powers in order to become Masked Rider.
 * Xena - Xena was the chosen one to fight all that is evil, although she was separated from her parents during war. For a brief of time, she went to darker path until eventually choose to redeem herself, starting her adventures as hero.
 * Ultramen: Ultramen are race of universe peacekeeper whom tasked to ensure peace and just in the universe. Some of them occasionally come to Earth everytime that planet was in danger and to hide their identity from public in that planet, they would either disguised as a human, choose a good-hearted human as both host and partner, and in lesser extent, bestowed their chosen human ally their powers.

Video Games

 * Mega Man - Mega Man was the second creation of Dr. Light/Dr. Wright after the failed Proto Man. Dr. Wily, a world dominator-to-be, wanted Mega Man dead or alive by turning Dr. Light's creations against the good doctor.

Western Animation

 * The Powerpuff Girls - Professor Utonium mixes the ingredients to create the perfect little girls using a mixture of sugar, spice, and everything nice. However, he accidentally spilled an extra ingredient called "Chemical X" into the mixture, resulting the little girls that he intended to be created, Blossom, Bubbles and Buttercup gained superpowers that they eventually used to fight crime.
 * Twilight Sparkle - Celestia and Luna are two royal sisters who ruled over the magical land of Equestria. The elder sister used her powers to raise the sun, while the younger sister brought out the moon at night. The younger sister became resentful because the ponies of Equestria relished daytime but slept at night. One night, she refused to lower the moon. She transformed into Nightmare Moon, a "wicked mare of darkness," and vowed to shroud Equestria in eternal night. Her sister used the Elements of Harmony to banish her to the moon, and took on responsibility for both sun and moon. All this is read by Twilight Sparkle, who is then tasked to study friendship in Ponyville.
 * Atomic Betty - Born on the planet Bane of Fragnog, she began training with her martial arts master, Spindly Tam Kanushu. As she grew up, she came to the planet Earth.
 * Bobby Generic - Born on Bobbyland, a bright and happy magical world where he can play, have fun and having the exciting adventures happen every day as Bobby uses his imagination. One day, Bobby is banished to Earth and meets the Generic family, Roger the dog and pig-tailed tomboy, Jackie.
 * Maggie - A little girl named Maggie loves her two soft toys - The Ferocious Beast and Hamilton Hocks. She has her magical imagination and has even dreamt up a whole new place called "Nowhere Land" where her toys have come to life and live. When Maggie was dreaming up Nowhere Land, she sat down with her magic crayons and drew a map of Nowhere Land. To her surprise the map sprung to life, using her magic and Nowhere Land existed from nothing.
 * Bibi Blocksberg - After Bernhard and Barbara Blocksberg got married, Barbara mixes magic potions and ingredients to create her own daughter and then Bibi Blocksberg is born
 * Turbo Teen - Brett and his car were driving through a stormy mountain, and then a tree swerved them off the road into the path of Dr. Chase's experiment. He and his car are now one — Turbo Teen.
 * He-Man and She-Ra - They were brother and sister twins, separated due to their enemies Hordak and Skeletor. He-Man lived in Eternia, She-Ra lived in Etheria. They later join forces to fight evil.
 * SuperTed - He was a discarded toy given life by Spotty and superpowers by Mother Nature, which allowed him to fight evil.
 * Optimus Prime - In the cartoon, Optimus Prime, his Autobots, and the Decepticons, led by Megatron, are at war with each other until they crash landed on Earth in a 4-million-year-old sleep. That is until they scanned vehicles, weapons, and animals in order to become the Transformers we know. This includes Optimus Prime, whom scanned the truck his trademark vehicle form is now. Also, before revealed to be destined to become a Prime, Optimus was used to be a regular Cybertronian named Orion Pax and depend on the writer, may used to be former friends with Megatron.
 * Danny Phantom: Danny was an ordinary 14 year old kid until a freak accident with his parents' portal generator to ghost world causes his DNA imbued by ectoplasm from the said world, mutating him into human-ghost hybrid (human being with ghost powers).
 * Ben Tennyson - Ben was used to be ordinary 10 year old boy whom discovered an omnitrix, alien technology which enable him to morphed into various alien lifeforms (started from the first 10 due to lack of technical knowledge about the device) that he later used to save the world from rogue aliens. He even later learned the fact that the Omnitrix can also used to restore endangered alien that close to extinction.
 * Biker Mice From Mars - They came from Mars, their world that was enslaved by Plutarkians (1993) and Catatonians (2006), to our world. They consist of Modo, Vinnie, and their leader Throttle.
 * SWAT Kats - Jake and Chance used to be members of the Enforcers, and while pursuing Dark Kat the first time with Commander Feral, cause considerable damage to Enforcer Headquarters. They are subsequently removed from the Enforcers and are forced to take a job at the Megakat City Salvage Yard to pay for the damage. There they use old airplane and engine parts to create the Turbokat and become the SWAT Kats.
 * Road Rovers - In the town of Socorro, New Mexico (one year prior to the formation of the Road Rovers), Professor Shepherd was forced to relinquish experimental transdogmafier technology to General Parvo in exchange for his lost dog, but instead Parvo gives him a bomb that destroys his laboratory. Next year, as normal dogs begin to mutate into monsters, Shephard, who miraculously survived the attack, takes measures to stop Parvo who is behind this. Shepherd selects five different dogs (Hunter, Blitz, Colleen, Exile and Shag) and in his new, secret underground lab, he uses his new transdogmifier on the five, turning them into "Cano-sapiens".
 * Mighty Ducks - In another universe exists a planet populated entirely by humanoid ducks. Dubbed "Puckworld" by its inhabitants, it is an icy planet, perfectly suited to the Ducks' favorite pastime, hockey. For the citizens of Puckworld, hockey was not simply a sport, but a way of life, occupying virtually every aspect of day-to-day existence. Legend has it that centuries ago, during an invasion by a reptilian race called Saurians, a duck named Drake DuCaine became the planet's savior over the Saurians' Overlords. The legend tells that DuCaine did so with a high-tech goalie mask. With it, DuCaine sent the Saurians to a mysterious "Dimensional Limbo". The last of the Saurians escape Dimensional Limbo and returns to Puckworld with an armada of robotic attack ships. The group of four is led by the last of the Saurian Overlords, Lord Dragaunus, who is assisted by his minions Siege, Chameleon and Wraith. They invade the planet and enslave the people of Puckworld. After some time, a resistance is formed by Canard, who has found The Mask of Drake DuCaine. With it, the wearer of the Mask could see through the Saurians' invisibility cloaks. Canard forms a band of Ducks to fight Dragaunus. The members of his team consists of Wildwing, Nosedive, Tanya, Duke, Mallory and Grin. They go on a mission to destroy Dragaunus's fortress the Master Tower and free the planet from the Saurians' control. While the mission is successful, Dragaunus and his forces manage to escape in their ship, the Raptor. The Saurians open up a dimensional gateway to escape through, but Canard and the others follow him into the portal with the Aerowing, intent on stopping them. Dragaunus attempts to get rid of the Ducks inside the portal by attacking them with an electromagnetic worm that will grow until it can swallow the Aerowing. In a desperate attempt to get rid of the worm, Canard sacrifices his own life by throwing himself to the worm. Before doing so, however, Canard gave the Mask, and leadership of the team, to Wildwing Flashblade, his best friend. Both the Raptor and the Aerowing leave the portal and enter a different dimension, landing in the Earth city of Anaheim, California. The Ducks meet Phil Palmfeather, a human who becomes their manager and makes them a legitimate NHL team. Their arena, only known as The Pond in the show, has a hockey rink that doubles as a landing pad for the Aerowing above and has a formal HQ below. On Earth, the Ducks and Dragaunus continue their fight, with Dragaunus's plans of conquest often curtailed by damage to the Raptor's power source and his efforts to find a new source of power, although there are other villains that also challenge the six Ducks.