Daughter of Hades Descendants AU TMNT (2012 version)

Harmony was found by Splinter shortly after he and his four pet turtles became mutants, she is only a month younger than Mikey so the five of them grew up together all raised by the great ninja master. Harmony however refused to learn how to be a ninja because she isn't human or a mutant at all. She has amazing powers and a single punch from her could kill anyone so she just decided to become her brother's secret weapon. After having many adventures with her brothers she learns something about herself that will change her life forever.