Hamato Karai

Miwa has been well-trained in high-level ninjutsu and hand-to-hand combat since she was a girl. Her weapons are a tanto and several shuriken. Her natural combat skills make her incredibly agile in combat, even equaling Leonardo's high level of skill. At will, she can transform into a mutant snake. Her snake form grants her several abilities, such as enhancing her hearing, speed, agility, stamina, stealth, and flexibility to superhuman levels, even granting her enhanced eyesight and night vision. Furthermore, Miwa can infect her victims with a highly toxic venom that is quite lethal within hours, but can be absorbed through the skin in seconds. When combined with her extensive ninjutsu skills and snake abilities, she becomes quite a formidable opponent. Some time later, Miwa learned to use her snake abilities to heal severe injuries she sustained (such as burns or bruises) by simply shedding the damaged skin and replacing it with a completely new one, similar to how a snake sheds its own.

Before the "Enemy of My Enemy" episode, Karai was more calm and even offered the turtles a temporary alliance. But when they broke the pact, Karai became more cruel, more ruthless, and wanted to kill Splinter and the turtles at any cost, just like Shredder. Karai was also quite inhumane; for example, she wanted to kill the innocent April in revenge for her mother's death. She also treated those below her in rank, such as Xever and Bradford, with no respect.

Everything changed when she found out that Splinter was her real father, Karai became kinder, but she still remained vengeful and wanted to take revenge on Shredder herself, which ultimately led to her mutation.

In Season 4, Karai remained vengeful and did everything in her power to destroy Shredder. She was also quite overconfident and rarely enlisted the help of her friends, hoping to destroy Shredder's empire alone, which often led to her defeat.

Miwa, also known as Karai, has black hair that's lighter at the back. She wears several black earrings and red eyeliner on her upper eyelids. She has amber eyes. She wears a jumpsuit with silver armor, a black material worn under her armor, traditional Japanese shoes, and a purple belt.

In her horned viper form, Karai has white skin and green eyes. She has no hair. Instead of hands, she has snake heads. In addition to her main mouth, she has another mouth at the back of her head, the purpose of which is unknown. She wears only armor. It's unknown how she changes her appearance, and how she manages to keep her clothes on.