Some TMNT stuff really isn't for little kids.

In the IDW comics, Krang is an Utrom from the planet Utrominon in Dimension X. Unlike their Mirage models the Utroms here are more warlike and have even built an intergalactic empire. Krang's father, Quanin, was a feared warlord and the last ruler of this kingdom before the imperialist efforts, their most important resource Utrominon (the basic material of the mutagen, which also transformed Splinter and the Turtles) was almost completely consumed and thereby almost the entire Utrom race had been extinguished.

When Krang was overthrown, Ma'riell became the new leader of the remaining Utrom survivors living on Earth's Burnow Island. Her humble peaceful regime became allied with the Turtles and Neutrinos who had been Krang's enemies.