This is a continuation of My Little Ninja Turtle, if you haven't read it, then you need to read it to read and understand this story
My Little Ninja Turtle (Part 1)
-------------------------------------------------------
Equestria is in danger, the Kraangs and the Hoof Clan are attacking and the Shredder nobody knows where he is, now Mane 6 and Turtles need to reconsider, leave differences behind and be friends again to save Equestria from these terrible villains.

(The story begins before Karai believes she is really the daughter of Splinter and after Mane 6 meets and defeats Starlight Glimmer)

The turtles went on an adventure in another world to saved it from the evil Kraangs, but for that, they needed to learn more about this new world called Equestria, luckily they meet the Mane 6, now the turtles and the Mane 6 needed to unite and save Equestria from the Kraangs and more enemies that are coming

(The story begins before Karai believes she is really the daughter of Splinter and after Mane 6 meets and defeats Starlight Glimmer)

This story is a sequel to I Love Being a Rainboom

A mysterious portal appears in front of The Turtles and Rainbooms while they were filming their own movie. They discover it to be New York, but a different one...with superheroes know as, the Avengers. Together, they will team up with earth's mightiest heroes and other heroes to fight many creatures and foes and put a stop the Avengers greatest and powerful enemy of all...Ultron.

Teenage Mutant Ninja Turtles (2012) x Equestria Girls x Avengers

This story is a sequel to Equestria Ninja Girls: Mind Over Mutant

Three beautiful young ladies, one of them, a member of the Hamato clan, the second, a member of the Foot clan, and the third, a member of both. Rarity, Karai and Adagio go on an adventure into a new world with new allies, defeating new enemies, and all while stealing back some goods.
Disclaimer: Neither Darth Wrex, nor I own Equestria Girls, Teenage Mutant Ninja Turtles (2012) or Sly Cooper.