While the term "Ultimate Intelligence" is typically associated with the TechnoCore's mission to engineer an omniscient AI, it is known that in the far future, the collective consciousnesses of humanity will give rise to their own Ultimate Intelligence. Like the Technocore UI, the human UI is a godlike being that resides within the Void Which Binds.
In the distant future, the human UI comes into conflict with its TechnoCore counterpart, resulting in a battle of unimaginable scale and destruction. The horrors committed during the battle deeply wound the human UI, to the extent that it jettisons the empathic part of its consciousness in order to survive the onslaught. The empathic segment of the UI is flung backwards through time, where it seeks out a human host to house itself.
In order to "flush out" the UI's empathic portion and its human host, the Shrike is created and sent back through time. It gathers victims from across time and space, subjecting them to eternal agony on its tree of thorns, with the intent of broadcasting their pain through the Void Which Binds and gaining the attention of the UI fragment.