Both Karai's human form and her snake mutation are playable in Teenage Mutant Ninja Turtles Legends.
TMNT Legends Bio
Karai is rebellious, anti-authoritarian, and driven. Shredder trained her to become one off the toughest ninjas in Japan. She's confident and shares a special affinity with Leonardo, seeing the heroic leader underneath the shell.
More animal than human, Karai-Serpent's rage controls her. It's very hard to reason for her, but there are moments when she recognizes the Turtles. She has some memories of her past and can return to human-like form, but not for long.