Leonardo - "Leo" is a hardworking ninjutsu student, learning how to be an effective leader for his three often unruly brothers. He wears a blue mask and fights with two katana swords called Niten Ryu. He also has a crush on April which his brothers all tease him about.
Donatello - "Donnie" is in charge of the design and manufacture of all of the tools and weapons in the Turtles' arsenal, and he is also a gifted hacker. He wears a purple mask and fights with a rokushakubo which converts to a naginata.
Raphael- "Raph" often lets his impulsiveness get in the way of rational thinking. He wears a red mask and fights with two sai.
Michelangelo - "Mikey" loves video games, skateboarding, pranks and pizza. He wears an orange mask and fights with two nunchakuwhich convert into kusarigama. Though he possesses a child-like innocence, Mikey always brings his best game to a fight.
Splinter - Splinter is the mutant rat leader of the entire family, and serves as a father figure for the Turtles. He once was a pet for a renowned martial artist, Hamato Yoshi in Japan. It was from watching Yoshi that Splinter first learned the art of ninjitsu which he then passes on to the Turtles. Splinter often acts as much as a spiritual guide and counselor to the team as he does their teacher. While he does not wield a traditional Japanese weapon, Splinter carries a cane which he can utilize as a weapon (like a bo staff) with fierce proficiency. Unlike the previous animated series, the Turtles often refer to Splinter as their father, rather than their master.
April O'Neil- The 16 year-old niece of Dr. Arnold O'Neil who likes to play video games and eat pizza. April befriends the Turtles after the Coal Soldiers kidnap her and her uncle. This incarnation of April O'Neil is African American and is depicted with pink hair.
Karai - A rebellious teen member of the Foot Clan and an expert kunoichi who stirs up trouble for the Turtles. She is an adoptive daughter of the Shredder.
Baxter Stockman - A technical genius and the scientist responsible for creating the mousers: a series of mouse-like robots that can eat through practically anything.
Jack Morris/Thundermutt - A famous martial artist and secretly a member of the Foot Clan, Jack Morris is ordered to New York with Zaxer. As Morris was previously bitten by Shredder's pet Doberman Pinscher Aquila, the mutagen transforms him into Thundermutt, a hunchbacked, dog-like mutant with a large spikes on his shoulders, a large hands, acute senses, and super-strength.
Zaxer/Slitherhead- Zaxer was an Australian street thug until Shredder indoctrinated him into the Foot Clan. As Zaxer previously touched his pet Spencer's goanna Rico, the mutagen transforms him into the lizard-like mutant Slitherhead.
Bebop - Bebop was a Spainish street punk until Shredder indoctrinated him into the Foot Clan. As Bebop was previously hitted by a warthog, the mutagen transforms him into the pig-like mutant.
Rocksteady- Rocksteady was a Jamaican street punk until Shredder indoctrinated him into the Foot Clan. As Rocksteady was previously snorted by a black rhinoceros, the mutagen transforms him into a rhino-like mutant.
Krang- The brilliant yet ruthless Utrom scientist who has become ally with the Foot Clan. He designed a tall, powerful android that resembles a gorilla. Baxter Stockman would build Krang a robot body that use him as a head. Krang can move the robot body in synchronism as if it were his real body. When his bodies aren't in use, he uses a much smaller bipedal machine known as a "dome walker" which is equipped with several weapons.
Coal Soldiers - An alien soldiers made of molten rock.