The Turtles :

Leonard : He's the brave and hopeful Leader. He will do anything to protect his brothers from danger but he can be a dork when it comes to star wars films. He's very spiritual but sometimes fearful, fearing he might loses his brothers like he lost his baby sister and mother. (He's 16)

Raph : He's hot headed and sometimes impulsive and impacient, he argues he think he should be the leader because he better fighting skills but he has a soft spot for his little brother Mikey. They bond a lot over video games and pizza. (He's 16 few months younger than Leo)

Mikey : Mikey has a thrill seeking side to him which drives Raph nuts. He loves to cook pizza (he makes good). He's very cheerful, funny, and exited all the time. He loves to skateboard,play with his cat, Kitty ,watch TV, and to hang out with Raph.  (He's 14)

Donnie : Donnie is super smart. He builds cool gadgets and vehicles.He studies Japanese  tradition. He's  nice but sometimes  gets annoyed with his brothers but he loves them. He has a crush on April. (He's 15)

Minor characters  :

Splinter
April
Casey (he'll apear sometime later)

Villains :

Shredder (of courses he's the main villain)

Karai: Same personitally but a lot more mischievous and deadly. But she has a remorseful side to her.

Tigerclaw

Bradford: He"ll become Razar

Xever: Hell become toka not Razar

Shinigami: A magical witch weilder and Karai's sister

Note: I hope you guys like this so far. Tell me what you think in the comments  below