TURTLES!!!
Not all of the turtles are together at the begining of the story, originally the only ones in Splinter's care, living in the sewers are Mikey, Donnie and Leo, but through the course of the story the three find more of their siblings!
Rapheal: The story begins with Rapheal finding his brothers--or really, his brothers finding him--he had been living on the streets, avoiding people, with no one besides himself. He spent his days hiding away from humans, finding food and searching for answers about where he came from and if he was truly alone in this world. One day when his searching leads him to a fight with another mutant, it apparently attracts the attention of his brothers and they are reunited! Raph isn't the best at being in a family--much less an oldest brother, but he tries his best and is incredibly protective of his brothers. He spent so long trying to find them, and now that he has them he won't let anything happen to them.
Michelanglo: Mikey is the acting eldest brother. He's goofy and playful and works very hard to take care of his two younger brothers, so when they're reunited with Raph, it takes a bit of adjusting to pass that role off to someone who is far less qualified. Still, Mikey is the heart of the family, he's always looking out for everyone and trying to make everyone feel at home, and despite the occasional arguments, he actually gets along with Raph great and is glad to finally have someone his own age around. While he may not appreciate his suggestions of snooping into the past that always seem to get Donnie and Leo into trouble, the two are very close. He's also very close with Don and Leo, making an effort to engage with their hobbies and be the best older brother he can be.
Donatello: Donnie is the quietest out of all the brothers and has the hardest time connecting with people, in stark contrast to Mikey. So, needless to say he doesn't initially appreciate the reuniting with Raph and how family dynamics have been shaken up a bit. However, Donnie is very invested in the idea of finding out where they all came from and tracking down the other mutants that apparently exist, and through that shared desire for knowledge the two bond. Donnie is definitely still the closest with Leo, with the two being twins and all. He's also just the most willing to be the guinea pig for all of his dangerous experiments. But uh--definitely the twin thing. more so. yeah.
Leonardo: (eugh I’m gonna try to keep this short) Leo is the baby of the family, however much he tries to deny it. He looks up to Mikey a lot, and dreams of being a great hero and leader just like he older brother, so when Raph comes along and is suddenly the oldest and thus in charge… he’s not happy. He doesn’t like the way he runs things, or how loud his music is, or how he’s just worse than Mikey, and Leo tells him this. The two get into quite a few fights. Besides that, Leo also spends a lot of time with his twin, Donnie, and is often testing out the various gadgets he makes, and he also spends a lot of time watching Power Rangers, Lion Force Voltron, and other similar shows.
Jennika and Venus aren't reunited with their family until much later in the story, so their descriptions are shorter due to spoilers :-)
Jennika: Jennika is probably the toughest of the turtles. She’s violent, similarly to Raph, but her love from fighting comes more from her relentless anger issues rather than an urge to protect her family. Despite this, she’s actually secretly a big softie who likes to listen to and play music, something she bonds with Raph over.
Venus: Venus, opposite to Jenny, puts forth an image of someone who is very calm and unbothered. Nonchalant, if you will (😭). In reality, she’s very opinionated about everything and when in private will NOT hesitate to tell her stupid brothers that they're being stupid. She’s also unapologetically girly, which isn’t too relevant but it makes me happy. She definitely keeps sticking bows onto all of the guy’s stuff, and Leo is the only one who doesn’t care.
HUMANS!!!
There are lots and lots of humans in NTMT as there is in TMNT!! And all of them should be familiar faces, even though their roles may have changed slightly. These people all come in at different points in the story, but they're all important, hence why they're here!!
April O'Neil is the turtles' closest friend and ally! She's a senior in high school, but met the turtles a few years ago when--after being ditched by her "friends" on a night out--they saved her from being robbed. Since then they've all been very tight, though she's definetly the closest with Donnie simply for their shared interest in computers and video games. April is a no-nonsense kind of girl and often the voice of reason among the boys, along with Leo. However, that doesn't mean she doesn't know how to have fun. She helps the turtles sneak around New York to get into SAFE trouble with her and often brings them new snacks to try or DVDs to watch when she visits them down in the sewers.
Casey Jones is another good friend and ally of the turtles! He met Rapheal back before he was reunited with the rest of his brothers, and the two were very close and remain that way even after meeting the rest of the turtles!! He's not as good of friends with the rest of them as he is with Raph, but he still gets along with everyone pretty well (not Leo... he's a brat). He also gets along pretty well with April and is absolutely head over heels for her, but she doesn't seem notice. Besides that though, Casey is a major jock, he's probably played every sport there is and he likes to spend his nights wandering around town doing wannabe vigilante stuff.
John Bishop is a paranormal investigator, trying to figure out where all these monsters that keep being reported are coming from. Of course, what he's looking for is the turtles and the other mutants running around New York, but he doesn't know that. His current theory is aliens, much to annoyance of his business partner Baxter Stockman, who is much closer to the truth than Bishop is. In all honesty, Bishop's characterization is BASICALLY just Shadow the Hedgehog from the fandubs???? He says a lot of vulgar stuff and cringe oneliners but his delivery makes it almost cool??? He also just radiates toxic man energy, which would be scary if he wasn't uh... stupid? I fear king barely made it out of high school.
Baxter Stockman is a scientist. What kind exactly?? Uh.... that doesn't matter!! He's helping John Bishop find the creatures that run around New York and determine what they are in hopes to finally be recognized for his great mind!! This is out of the ordinary for him since he usually works with computers and builds machines, but who says he can't dabble in biology?? He's a man of many talents after all. The only thing he really feels thats holding him back is how stupid Bishop is, however that's where his fund come from. Stockman is short tempered, rude and completely full of himself, always believing that he's the smartest person in a room.
Info about Oroku Saki will be placed in the same box as Yoshi and Splinter :-)
Oroku Karaiis the beloved, adoptive daughter of Oroku Saki. WHy does he have this daughter??? No one really knows, but he takes uh.. decent care of her and she loves him very much. She knows about the Foot Clan--though not the full extent of their actions--and wishes very much to be a part of it, though her father won't let her. She takes martial arts classes though in order to train for the day that she's finally able to help out and work at her father's side!! She's not interested in the science stuff he does though, even though Saki wishes she was. When she's not practicing her sick fighting skills though she likes to draw and watch old action movies. She's very serious and kind of mean, and thinks very highly of Saki, always trying to mimic how he acts, which means trying to act as nonchalant and uncaring as possible, even though deep down Karai has a very kind heart. ALSO it's spoilers how they meet but after they meet she has a VERY funny dynamic with Leo where she HATES him and he thinks they're best friends. Don't worry she warms up to him eventually and they watch Power Rangers together. I am surprised I wrote so much about her she's just very silly EUGH
MUTANTS!!!
Of course, there are other mutants just running rampant in New York!! All with different goals and alliances. Most of these are from existing TMNT media except for Marcel who is an OC but like... he's based off of that disguise Splinter had in one of the IDW comics so... yeah. Again, a lot of these guys come and go as the story progresses, but they're all relevant at one point or another.
Old Hobb is a disgruntled cat mutant created by the Foot Clan. He has since taken his own path away from the Foot Clan (and they are searching for him every day) but this doesn't mean he doesn't still have a vendetta against the turtles. After the death of his brother he swore vengence on both the turtles (who caused the accident that killed him) and the Foot Clan (who simply let him die). So now he's homeless and living out a sick revenge quest, often getting in the way of both the turtles' and the Foot's plans. He hates basically everyone, being rude and bitter to everyone he meets. He is very lonely.
Marcel is another cat mutant created by the Foot, as a replacement for the two they lost. They are a silly little kitty. They don't neccesarily care for the Foot's motives, but they do love all of the chaos that they get to ensue because of it and hey, they feed them!! They're pretty kooky and often say things that don't make sense. Their skilled in multiple different forms of combat and usually mix-up fighting styles a lot. They take joy in being difficult and making other people annoyed or angry.
Alopex is another mutant made by the Foot, she often works with Marcel to carry out orders, though she much higher ranked due to her ability to actually take things seriously unlike her cat counterpart. She's a serious for the most part, but she's also pretty snarky and likes to show-off, which causes her to loose track of what her goals are sometimes. She's very loyal to the Foot, but does have like... a thing?? going on with Raph??? There's just like a lot of hate flirting it seems like??? Who knows what that's about. Alopex is a very skilld fighter, but unlike Marcel she only really practices ninjitsu, she can easily wip out plenty of Foot Soldiers though, easily one of their strongest fighters.
Leatherhead is a mutant alligator, created on accident!! A problem with disposing some mutagen which led to it ending up in the sewers where Leatherhead was then mutated. He's good friends with the turtles, having met them whe Mikey ran into him while skatboarding down the sewers. He's not very smart but he wants sosososoosososo badly to be a scientist, inspired by his own mutation to learn biology. For this reason he mostly hangs around Donnie, who finds him very annoying.
