Rise of the TMNT verse, set post movie. The Dread Lord Sh'Okanabo has taken an interest in Earth, and with assistance from Baron Draxum, he creates alien/mutant clones of the Turtles, raising them to become killing machines and the harbingers of his conquest. After the Krang are defeated, decides to try and take the planet while its forces are weakened.

(clone turtles can be found on @theterrorpins)

Sh'Okanabo is considered a myth to many, an intergalactic boogieman that lingers in the shadows. In reality, the Dread Lord has hidden himself on the Earth to begin what he calls the Day of Awakening, and conquer the planet for his people, the Kanabo. 

(this verse takes place anywhere between the beginning of Fast Forward to right before his death). 

tba