The decisive battle of the Oracle war was fought around the cluster mind of the All-Seeing Sybil, a thousand light years below galactic plane, which was attacked by several fleets of relativistic vessels from Keter and the Negentropists.
These fleets had been en route since the start of the war, perhaps longer. The fleets were preceded by a synchronised attack by Nicholl-Dyson beams. A decade of destructive warfare followed, as the fleets used immensely powerful transapient weapons against the damaged cluster brain, while suffering severe losses themselves. However the war suddenly and finally ceased when the Sibyl disappeared, with all her data and sunroutines vanishing overnight. She is presumed to have committed full data suicide, although there is no real certainty as to Her fate.
The cluster has been combed for data caches and booby traps, with no results. No usable data remains in any of the processing substrates in this cluster, which were formerly used by the Oracle Machines to predict future trends and develop strategies of infiltration and war.
A widespread myth or rumour has emerged which holds that the Sibyl made Er escape into the bulk; it is widely believed that archailects are capable of operating beyond the confines of our immediate braneworld, but always with intimate and extensive connections to substrates in our universe. If the Sibyl fled into the bulk then there seems to be no known route for a return.