Teenage Mutant Ninja Turtles #21
- Publisher: IDW
- Written By: Kevin Eastman, Tom Waltz
- Art By: Kevin Eastman
- Language: English
- Digital Release Date: March 12th, 2014
In this special issue drawn by TMNT co-creator Kevin Eastman, the Turtles have struggled to survive against unstoppable enemies and impossible odds. The time has come for the next stage of their training to begin. The lesson turns deadly, though, when a mysterious new opponent arrives and teaches the Turtles they have MUCH left to learn!