Echidna history has been revealed in Sonic Adventure and Sonic Chronicles: The Dark Brotherhood. The echidna race was split into two tribes, the Knuckles Clan and the Nocturnus Clan, which warred against each other. The Nocturnus Clan was more technologically advanced (and was later documented as the "Fourth Great Civilization"), possessing powerful combat robots named Gizoids. In an attempt to gain power enough to defeat the Nocturnus Clan, the leader of the Knuckles Clan, Pachacamac, raided the Master Emerald altar in an attempt to gain the power of the Chaos Emeralds. This action caused the Emeralds' guardian, Chaos, to go berserk, destroying much of the Knuckles Tribe and, subsequently, much of the Knuckles Clan territory rose into the sky.