A little short for our good ole Leatherhead of the 2012 tmnt series
Splinter found his youngest son in his room all curled in the fetal position, letting his tears fall from his eyes. It was merely an hour ago since they had heard the shocking revelation of the Kraang's plot for April. Michelangelo had a pouty looking face on as he sniffled a bit. The mutant rat sighed and walked over to his son, resting a hand on his shoulder. The youngest turtle looked up and gave him a very sad look. Splinter was at a loss for words to say to his son. He knew he was grieving for his friend, Leatherhead. Despite the dangers the mutant alligator presented, his son found a friend in him.
"He sacrificed himself to stop that big rock Kraang thing." Michelangelo trailed off, not finding the strength to finish as he began to bawl again.
Splinter sat down by his son and pulled him close, aware of the watching eyes from the doorway. They were all affected by this...
...
Meanwhile in Dimension X...
The Kraang drones fled in terror as the terror they had created chased after them. One was unlucky and ended at the jaws of the beast. The others ran while the soldiers came and began shooting. Their weapons only angered him more as the beast roared out their name and charged. A trail of destruction followed in its wake. It wouldn't be long before they captured in but the beast would make damn sure these monsters felt fear.
Leatherhead tore at another Kraang drone, fluids leaking out of his mouth and covering his body. His eyes had been covered by the thin membrane that indicated his rage. The Kraang had good reason to fear him. He was the Frankenstein they had created. And he was showing his creators what monster they had made. The toxic air that had affected the turtles and humans did not affect him. He was created here in this dimension and so he was accustomed to it. More Kraang droids showed up and slowly, they began to overcome him. He would not submit to them without a fight. In fact, he'd rather die than become their experiment all over again.
Yet it seemed fate had a different idea as he was subdued and thrown in a cage. The Kraang were to run tests on him and see what new things they could learn from him. And possible use him to their advantage for the planned invasion. Leatherhead now began to feel regret for all the harm he had caused to his friends and any other innocents. If these aliens had their way, he may be forced to hurt them again. But he was smart. He could make the Kraang believe that he has all but given up and give them false ideals.
Yes, that would work. And he'd wait for an opportunity to get back to Earth and find the turtles. Hopefully, it wouldn't be too late by then...