Jennika, also known as Jenny or Jenn for short, was the ninja chūnin of Splinter's Foot Clan, a dear friend to the Turtles and for a time was a love interest to Casey Jones. Originally human, she is now a mutant turtle after her life was saved by an emergency transfusion of mutagenic blood donated by Leonardo due to her loss of blood. After the City at War arc she moved to Mutant Town a part of New York inhabited by people who were mutated because of Old Hob and his bombing at Union Square Park.