Teenage Mutant Ninja Turtles.

Shredder (real name Oroku Saki) is a supervillain and character in the Teenage Mutant Ninja Turtles franchise.
Oroku Saki is a martial artist and the leader of the Foot Clan, a criminal syndicate composed of loyal ninjas, gangsters, and scientists. Shredder's backstory varies depending on the comic/animated series/movie in which he appears. The original Shredder was Splinter's archenemy, vowing revenge for the death of his teacher, Hamato Yoshi. To this end, he trained the four Mutant Ninja Turtles in ninjutsu. Splinter's students defeated Shredder, but Oroku Saki's legacy lives on in the form of his comrades, whom the Turtles subsequently encountered.

Splinter is a mutant rat and the mentor of the Teenage Mutant Ninja Turtles. He trained them in martial arts and also acts as their adoptive father. Splinter is intelligent, wise, and patient. Depending on his media incarnation, he is either a mutant ninja named Hamato Yoshi himself or his pet.

Nicknames: Stick Guy, Hockey Player, Puck
Casey Jones is the central character and tritagonist of the Teenage Mutant Ninja Turtles (2012) animated series, a friend of April O'Neil and an ally of the Teenage Mutant Ninja Turtles. He is particularly close friends with Raphael and Donatello. He is a human teenager from New York City, a hockey player, and a student at Roosevelt High School. Before meeting April, he had numerous encounters with mutants and the New York criminal underworld. This inspired him to become a vigilante, and he later met the Teenage Mutant Ninja Turtles and Splinter, who were April's "secret friends."
Description: He has helped April more than once, saving her life. He often calls April "Redhead" or "Redhead." In "The Good, the Bad, and Casey Jones," he made his own equipment and met the Teenage Mutant Ninja Turtles (first with Raphael). He initially considered them evil and crazy, but soon learned of their friendship with April. He wears a torn hoodie and a hockey mask with a skull, and sometimes paints his face with a similar design. He wields a bat and stick, throws pucks, uses a homemade stun gun built into his left glove, and bombs made from spray paint cans or hockey pucks with firecrackers attached. He also fights with various improvised objects, such as steel pipes. He has folding roller skates that he can quickly deploy. He is left-handed. He competes with Donnie for the love of April.
Appearance: Casey John appears to be a teenager, about 16 years old. He wears a hockey mask with a skull painted on it. He is armed with two hockey sticks and a baseball bat. He wears folding roller skates. He may have lost both of his front teeth in battle.
In the "Requiem" episode, he loses his hockey mask and makes himself a new one, this time made of metal. It has no designs on it.

Nickname: Redhead, Ginger
April O'Neil is the central character and one of the deuteragonists of the series, as well as a friend and ally of the Teenage Mutant Ninja Turtles.
Description: A sixteen-year-old girl, the daughter of Dr. Kirby. She wears a yellow headband, a dark green long-sleeved T-shirt and a short-sleeved yellow T-shirt with white stripes and the number 5 over it, short blue denim shorts, gray tights, white knee-high socks with two blue stripes, and black boots. She also wears brown bracelets in the ancient Egyptian style. Her red hair is shoulder-length, but pulled back into a braid. She also wears her bangs parted to the right. She has large blue eyes with long eyelashes and freckles. She has a thin and slender build. In space, she wore yellow overalls with pockets and white boots. When she became a kunoichi, she began wearing black overalls with pockets and a yellow stripe on the sides, black boots, and a black headband. She keeps track of unusual city incidents on her laptop. Loves spending time with friends playing video games and eating pizza.
Character:
She has a friendly and compassionate personality. She's also quite stubborn and sometimes reckless, willing to take risks. She also takes harm to her loved ones very personally, which is why she temporarily stopped interacting with the Turtles at the beginning of Season 2, as they were responsible for Kirby O'Neil's mutation. But after realizing that not everything depends on them, she forgave the Turtles. She's also quite intelligent.
History: April was born to Kirby O'Neil, a scientist and psychologist, and his wife. As a result of Kraang experiments on her mother and her ancestors, April inherited a genetically altered human/Utrom gene pool. But April was different from her other relatives in that she was the perfect completion of the Kraang project to create a human with the necessary signature to reshape Earth. It is unknown when Kirby learned the truth about his daughter and wife. Later, while they were living in Northampton, when April O'Neil was six years old, the Kraang came to take April O'Neil away, but she was saved by Kirby.

Nickname: Mickey (Mikey).
Michelangelo: A mutant turtle with an orange bandana. He's the most positive and cheerful member of the team.
Description:
Mickey has light green skin. Michelangelo also has blue eyes. He is the shortest of the turtles and appears slightly plump (though this is due to his shell). He also has freckles on his face. He wears an orange bandana with the shortest ends and brown bandages on his legs and arms. He wears a belt without a forearm (like Raph).
Character:
Michelangelo has a cheerful and naive personality. He's quite slow on many things, but can sometimes remember complex ones, as he has a photographic memory. He's very naive and believes in many things, like leprechauns. He's also easily tricked, as Chris Bradford did. However, Michelangelo can also be focused and serious when something threatens his brothers.

Nickname: Donnie
Donatello is Splinter's third adopted son and Karai's adoptive brother, but he is the biological brother of Leonardo, Raphael, and Michelangelo. Donnie is a scientist, mechanic, and inventor, responsible for the development and production of all the tools, gadgets, armor, vehicles, and weapons in the Turtles' arsenal, as well as a talented hacker. Wearing a purple headband, he fights with a bo staff, which also transforms into a naginata (a Japanese halberd) using the blade at one end of the wooden staff.
Description:
Donnie is a mutated, anthropomorphic, olive-skinned teenage Ninja Turtle. Unlike all his previous incarnations, this new, updated version of Donnie has a gap between his teeth in addition to a taller, more slender frame. He has large, red-brown eyes and an egg-shaped head. Like most incarnations, he wears a purple mask, the tails of which are longer than those of any of his brothers except Raph.
Character:
Donatello is incredibly creative and intelligent. He is an incredibly skilled scientist, having a "path with machines." He is a skilled scientist, mechanic, and mathematician, and is also an expert in many fields of science. He has devoted much time to studying technology, biology, physics, chemistry, mathematics, and metallurgy. It is Donnie who invents many machines and gadgets that can be useful in battle.

Nickname: Raf.
Raphael is one of the four protagonists. His headband is red.
Weapon: Two sai
Description
He appears to be a mutant turtle with green skin (Raph's is the darkest compared to the others). He is one of the shortest members of the Turtle team (Mickey is shorter than him). He has an angular head and large, green eyes. He has a crack in his left plastron. He also wears a dirty red headband and has the longest ends of his headband of any turtle.
Character
The most hot-tempered member of the team. Aggressive, choleric, and easily provoked. He can't control his anger and is driven by his emotions rather than controlling them. Splinter knew about this vulnerability and taught him self-control. Despite his aggressiveness, he is a reliable brother with a big heart, ready to watch his family's back in times of danger and fight to the end.

NICKNAME: Leo.
Leonardo is the most experienced ninja of the brothers. His headband is blue, and he wields two katanas.
Description:
He looks like a green mutant turtle. He's average height compared to his brothers. He wears a blue bandana and wields two katanas. His eyes are blue. He enjoys watching the show Space Heroes, emulating his idol, Captain Ryan.
Character:
Leo is the team's leader and shoulders his responsibilities, which sometimes trouble his brothers, especially Raph. Leo is the level-headed and calm one of all the brothers. He is also the most serious and disciplined of the turtles, and therefore, of course, their leader. He bears a great deal of responsibility, which can sometimes overwhelm him. Overall, Leo acts as an older brother to the turtles and an older son to Master Splinter.