Ninja in Disguise (TMNTxROTG)

When Kai was born, she was inherited from Hamato Yoshi, who was her loving sensei/father. Her name means new in Japanese. There was this shadow that snuck into her room one night and took her away from her father and her home at a very, very young age. Hamato Yoshi, later went to buy turtles and then he got mutated by the Kraang and…well.. Only true TMNT fans know what happened after that.
15 years later, Kai is living a perfect life with her kidnapper, Pitch Black. She goes to a high school and have friends that she can trust with multiple secrets.
Hamato Yoshi, now called Master Splinter by his turtle sons, continues to try and search for Kai. He doesn’t let his sons go up to the surface until he finds his truthful daughter.//