 A power struggle ensues between the IsoDidact and other Forerunner commanders who think the Ur-Didact should instead lead them.The Master Builder manages to regain control for him and the IsoDidact by revealing that the Ur-Didact is being used as a pawn for the Gravemind; after Faber had recovered him, the Ur-Didact conveyed him a sadistic message from the Gravemind which had absorbed Faber's family.A massive Flood fleet led by Mendicant Bias arrives and chaos erupts.