Brethren

Brethren -- true name Cheyenne, identified by Hadrian as female -- is the last Mericanii daimon and sole survivor of the Foundation War. It dwelt in the underground reservoir of Vorgossos for millennia, growing into a titanic mass of fused flesh and machine, and controlled Kharn Sagara's vessel the Demiurge as its ship's daimon. Hadrian destroys Brethren on Vorgossos by draining the reservoir, and Brethren foresees and accepts this death in service of a larger purpose.

Hadrian comes to understand the full scope of Brethren's plan. Siding with humanity rather than its own kind, Brethren helped build the Demiurge. Through its prognostication engine it knew Hadrian would come to Vorgossos and when, and it orchestrated the sequence of events that shaped his path: aiding Switch in summoning Bassander Lin to force Sagara's hand, ensuring Hadrian's meeting with Aranata Otiolo, and even arranging Hadrian's death to set him on the road back to Vorgossos. Most critically, Brethren designed Orphan knowing that Orphan would one day help destroy it, and that Hadrian would need Orphan's aid in the wars to come. Hadrian speculates that Sagara withheld the Archontic arsenal from Brethren despite ceding command of the Demiurge to it.