The Turtles first encountered these creations in "Origami Tsunami", when they caught up to the paper thieves. The Foot Lieutenant began creating Origami Ninja and sending them against the Turtles. However, the Turtles manage to defeat the Origami Ninja (as well as a a much larger variant), and activate the sprinklers to get the stolen paper wet, so that no more could be created.
The standard Origami Ninja come in two variations: the first type is slender and bluish-black in color, and the second type is bulkier and maroon in color.
It is possible that only the Foot Lieutenant has the ability to create Origami Ninja.
The Foot Brute was briefly seen attempting to do so, but he only managed to make an ordinary paper swan.
Origami Ninjas can be formed different sizes depending on the the paper, size or amount, used to create them.