The Nocturnus Clan, also known as the Nocturnus, the Nocturnus Tribe, the Marauders, the Fourth Great Civilization, and the Dark Brotherhood are a rival clan of the Echindas who used to be from Sonic's world 4,000 years ago but in their moment of triumph, a dark force wrenched them from their home and into the Twilight Cage. They are the titular main antagonists of Sonic Chronicles: The Dark Brotherhood and they are led by their leader named Imperator Pir'Oth Ix.
The technology they use to do battle with is very advanced. So advanced they even have Gizoids, which they created anyways. When they attack, they can usually take some of your HP away from you.