1) Splinter was the pet of tang shen and Hamato Yoshi all three immigrants wanting to escape the wrath and impending fury of there previously friend Oroku Saki.
2)Yoshi is killed by Shredder but in turn is scared and loses an eye from the interference of Splinter.
3) Splinter finds the turtles abandoned in the sewers covered in the ooze after a truck spills some during a car chase trying to escape the earth protection force. Splinter takes pitty on them and brings the turtles to his burrow and after a night they mutate into humanoids Splinter into an adult and the turtles more toddler like and raises them for 15 years training them into the ninjas we know
4) The turtles were a mismatch 4 pack of clearance pet turtles all 4 different species. Leo a common musk, Raph a red slider, Donnie a soft shell, and Mikey a painted. The clothes the turtles wear reflect their personalities. Leo wears traditional ninja-yoroi in a navy blue along with a blue mask that wraps around his face, he keeps a utility belt of kunai with katana sheaths attached to it. Raph wears camo shorts and a torn up red hoodie as well as his mask he keeps a belt with his sai and smoke pellets on at all time. Donnie wears a metallic back pack he calls a battle shell to protect himself better in battle he also wears a pair of glasses ovet his purple mask and overalls with a ton of pockets for tools. Mikey like raph wears a hoodie but orange with his nunchucks hidden in the pocket and wears jorts with deep pockets for trinkets, he also keeps a strap on his back to hold his skate board.
5) Shen is paralyzed from the waist down during the fight with shredder and forced to become Shredder's wife. She soon gives birth to half sibling daughters the older the child of saki the younger the daughter of yoshi. (I asked and researched if twins can be born with different fathers and it's super slim but possible)
6) Shredder raises the two girls as his own beginning their training as soon as they can function properly for katas. The older twin he names Karai who is his blood daughter the second Shen names Jennika and she is yoshi's daughter.(the 2 have an azula zuko relationship)
7) The reason the ooze exists is from experiments an utrom named mortu disguised as the human Professor Jordan Perry did to recreate fule for his starship so he can take the criminal chr'ell leader of the utrom terrorist organization the kraang back to their homeworld to face justice.
8) Chr'ell is leader of the kraang an organization of utroms bent on overtaking the universe and was trapped on earth with mortu. He escapes and hides from his captor and infiltrate the human government becoming leader of the earth protection force agent John bishop to gather technology to take over earth then the universe.
9) Baxter Stockman was once apprentice to professor perry but when the professor disappeared Stockman inherited his company, tcri. Baxter took the company perry built renamed stocktronics fueling his ego getting rich and becoming the Shredder's go to tech man as well as his supplier of modified mutagens.
10) Shredder only sends out his ninjas when he senses a true enemy is in new york so he uses the leader of the purple dragons Arnold "Hun" Jones a gangster that had been modified by Stockman with a version of the ooze mixed with steroids making him a behemoth.
11) The nightwatcher is a hockey masked hoodlum named Cassandra "Casey" Jones. She is niece to Hun wanting to stop her idiot uncle from destroying new york and wanting to get him to reconnect with Cassandra's mother his sister Shadow Jones.
12) April O'Neil is the daughter of Elizabeth O'Neil and Baxter Stockman. Her mother was once Stockmans wife and assistant but got sick of his ego divorced him and took april with her. She's quite bombastic and is best friends to Casey Jones. She and Casey met the turtles by accident when the turtles were trying to find Splinter and a new lair.
13) After shredder found out about the turtles he steals blood samples from them using their mutagen laced DNA inhancing it into a more concentrated ooze. Stockman then created Shredder his own team of kinda clone mutants. The first was a box turtle injected with concentrated Leo mutagen DNA turning him into a bulkier blue version of Leo named Slash. The second a giant alligator Snapping Turtle injected with Raph's DNA turning him humongous and coated in spikes this one was named thrash. The next was a not a Turtle but a marbled salamander injected with Donnie's DNA making a turtle salamander hybrid named lash. Then the last was a yellow bellied toad injected with Mikey's DNA making another hybrid that named itself crash.
14) after months of fighting between the foot and turtles Splinter avenged his master killing the Shredder thanks to the assistance of shen and Jennika. Karai witnessed this and went feral pouncing Jennika stabbing her in the abdomen. After this Jennika was given a blood transfer from Leo turning her into a mutant musk turtle as well. Baxter Stockman was damaged horribly during this so karai had his brain put in a jar so she could continue to use his knowledge. Hun and the clones left the foot turning his gang the purple dragons into a criminal syndicate. Jennika and shen joined the turtles in their lair finally with a loving family. The now insane karai decided with the death of her father and betrayal of her mother and twin she dawned the mantle of Shredder.
15) after the death of Shredder the city ends up in the middle of a criminal power vacuum the turtles are put in the middle of. And karai makes it a hundred times worse by taking her four most trusted foot soldiers and mutating them into a monstrous wolf named Rahzar, a sharp shooting tiger called tigerclaw, a hammer head shark named Bludgeon, and a blood thirsty falcon named koya.
16) during a battle on a foot transport truck where Stockman was moving excess mutagen some of it spilled in central park mutating an albino sewer gater, a male white hare that ran away from his magician, a dope of a pigeon that was waddling around, and an arctic fox that had escaped the zoo. The four were taken in by the turtles after they mutated. The gater was named leatherhead he's a gentle giant that found a love of technology with donnie. the hare was named Hokum and made himself at home in the kitchen and friends with tang shen deciding he'd help the Hamato clan as a chef and shens helper. The pigeon named himself Pete and didn't really know what he'd do but he and Mikey clicked and became friends with comics games and art. The fox however was another story. She named herself Alopex and didn't want to be locked up again but had no where to go so agreed to join the ninjas as a student of Splinter and shen.
17) the turtles befriend a blind chef named Murakami Tatsu who is secretly a ninja mystic known as the ancient one who watches over those he finds interesting judging if they're worthy of his training.
18) throughout the turtles adventures they end up making a few human friends like investigative reporter Jack Kurtzman and his daughter Irma. a pizza delivery boy named keno who's also a martial artist that starts to train under Splinter, Hun's son Sid Casey's cousin that tries to become a purple dragon and his older sister Angel. A former stocktronics scientist named Harold Lilja who's pretty eccentric and left so his inventions couldn't be used for evil. And the Timestress in training Renet who accidentally sends the turtles to prehistoric earth for a bit while trying to stop a villian.
19) When the turtles and Renet returned to the present a velociraptor and baby protoceratops jumped through the portal. Karai got ahold of the raptor keeping it as a beast she releases on foot ninjas that failed her. The turtles took in the baby protoceratops naming her pepperoni raph essential becoming her momma.
20) after multiple losses Karai Shredder was done with the turtles and her own incompetent minions. So she had Stockman make a special blend of mutagen. A cocktail of the hun steroid ooze, and multiple snake DNA. She injected herself while fighting the turtles and their allies turning into a serpentine super Shredder.
21) After the turtles defeat the monster karai and disband the foot, Bishop/chr'ell peaks his head out ready to make his move. He takes in Stockman brain using a bribe of gifting the former scientists his company and body back if he could find professor perry and build him a warship to take over earth then the universe.
22) While Hun had his dragon syndicate and the clone turtles he thought more muscle would help. When the karai went down koya and rahzar unwilling joined bishop. Tigerclaw went m.i.a. most think he went solo as a bounty hunter. Bludgeon joined the turtles wanting to find a better path. Leaving Karai's raptor homeless alone eating garbage and rats until Hun found it. After awhile Hun got ahold of some ooze and turned a few of his willing punks and gangsters into more mutants as well as the poor time displayed raptor. A duo named Bebop and Rocksteady turned into a tusked boar and Rhino both loving the new strength and took the mutant raptor under their wings as a new friend and sadly naming him Anchovy. One of Hun's best enforcers a guy named xever sadly got turned into a snake head fish but with a bit of stolen stocktronics tech he got some new legs and a fancy water pack. One big fat guy whos a major jerk got turned into a werid spider. Then the last guy called snake was turned into some kinda plant mantis monster.
23) after months of fighting bishop/chr'ell and finding prof. Perry/mortu, bishop wins. So the turtles, april, Casey, alopex, mortu and his friend the Fugitoid have to race through the galaxy to the utrom homeworld to save the earth and stop Chr'ell's plans. During this the turtles befriend the triceratons a race that was devastated by Chr'ell and his minions destroying their homeworld leaving only small colony asteroids run by Kraang slavers. The few warrior triceratons lead by Traximus agree to help free earth along side the turtles.
24) during the space race to the utrom homeworld Chr'ell sends Koya, Rahzar, Stockman (now in a robotic mech suit) Mindless mutant karai, and his own personal mutants The mutagen man a super soldier gone wrong that mutated with the bacteria in his stomach into an acidic monster that has to be contained in a suit that allows him to expel his acid as a weapon, and The Newtralizer a mutant Newt outfitted in tons of alien weapons created as Chr'ell's personal hunter.
25)while the turtles and others are in space their allies and surprisingly enemies like tigerclaw even hun and his goons form a resistance to fight Chr'ell and his forces becoming the mighty mutanimals a group composed of Hamato clan and purple dragon mutants lead by Splinter, Hun, and Tigerclaw.
26) the turtles make it to the utrom homeworld and get the help of the utrom armada as well as the triceraton warriors. They return to earth and attack Chr'ell's stronghold the technodrome created from multiple alien technologies he's collected over the decades as head of the Earth Protection force.
27) the turtles defeat chr'ell but at a cost. Chr'ell rigged multiple mutagen bombs across the city enough to mutate the entire earth. The mutanimals are able to disable all but one. Splinter was able to take put the major explosive but died in the process. A smaller secondary explosion occurred though mutating a good chunk of Manhattan.
28) the newly appointed mutant town was barricaded off from the rest of Manhattan during the cleanup of Chr'ell's invasion. The turtles soon moved in after their master's funeral to help all the new mutants adjust to the situation. Mutant Town took over the entire smaller neighborhoods ofAlphabet City, the Bowery, the East Village, NoHo, Peter Cooper Village and Stuyvesant Town, and fragments of the Gramercy Park, Little Germany, Little Italy and Nolita. The southeast triangle-shaped portion ofUnion Square Parkis also located in it, while the rest of the park lies to the west outside Mutant Town.
29) during the war Hun and the Jones family were able to reconnect and he turned over a new leaf using his connections to fund assistance and construction for mutant town. Other allies of the turtles also helped the utrom made a full apology to the people of Earth for the actions of Chr'ell and helped relief efforts world wide. The triceratons were found a new home but some chose to stay on earth as a continued thank you to the turtles. Leo Jennika and Alopex opened the Splinter dojo to help mutants learn to defend themselves as well as help some that were having difficulties figuring their new forms out. Koya Rahzar Stockman were tried innocent being forced to help Chr'ell but they and others were imprisoned for past misdids that couldn't be undone.
30) during the time right after the M-bomb lots of mutant town was dangerous normal people were confused and others were scrambling for power. Big players wanting power was the Rat King, Don Silverback and his mutant apes, The Punk Frog gang and lots of others. But with the turtles and mighty mutanimals they were able to stop them and help make mutant town into a home for the misplaced inhabitants.
31) after mutant town becomes a livable city for it's mutant inhabitants thanks to Mutant Town's mayor Arnold Jones former purple dragon syndicate leader. With Mayor Jones' financial persuasion with the the rest of New York five years after the M-bomb mutant town was reopened to Manhattan letting humans and mutants live together in harmony.
32)after the years and constant battles the ancient one finally ffinds the turtles and friends worthy. After a month of training he takes them all to the realm of the Battle Nexus to fight for earths honor to become battle nexus champion. When the go to the realm they meet the rulers. A Jorogumo named Big Momma the original champion, her husband, The Daimyo, master of the nexus, and their son Ue the ultimate ninja who has trained his entire life to take his parents place as master of the nexus.
33) When the turtles are entered into the tournament the ancient one gifts them with mystic weapons known as The Fangs of the Dragon. Leo was gifted Gunshin a powerful odachi sword with the ability to shoot flames and open portals. Raph was given Ōyama a set of tonfa that grant him to ability to coat himself in his astral form. Donatello was given Byakko a yari spear able to cast and expel giant gusts wind. Mikey was given Inazuma a Kusari-fundo that's chain can extend infinitely and can cast lightning but the blade it has is possessed by a goblin spirit so he must tame it for control. Jennika was given Banrai a set of twin chain sickles that grant her the ability to control the earth and split mountains. Alopex was given Mō fubuki twin axes with the ability to manipulate ice.
34) during the tournament they fight and meet new friends and rivals. From a alternate earth an anthropomorphic Rabbit Ronin name Miyamoto Usagi and his rhino friend Gen. A warrior alchemist named Baron Draxum and his two gargoyle assistants Huginn and Muninn, and Lord of the Demodragons Kavaxas.
35) this tournament turned bad though with the ultimate ninja betraying his parents with the assistance of drako son of Kavaxas as well as Draxum. The ultimate ninja was going to use Draxum's alchemical powers to take his parents powers and drako as a distraction with his desire for revenge from when Splinter humiliated him.
36) during the tournament after both lost Mikey and Jennika are able to stop the plot of the ultimate ninja and his accomplices forcing the Daimyo to banish them all from the nexus forever. And the tournament ending with Donnie as champion.