Nearing the end of their work on the Ring, roughly 4 million years from the present, the Xeelee constructed several hundreds of enclosures to return to the beginning of their history 13.5 billion years ago. These enclosures, call Sugar Lumps, appeared as enormous glowing cubes varying in size from a few thousand to tens of thousands of kilometers on a side (capable of enclosing moons or planets). More than a simple Closed Timelike Curve, the Sugar Lumps are described as having a negative vector in time (i.e. traveling backwards in time via a time symmetry) and function as inverse time capsules. When the Sugar Lumps arrive at their destination in the distant past, the Xeelee would emerge as a fully developed race with their knowledge of future events and be able to immediately initiate their grandest projects against the Photino Birds.
The Sugar Lumps are guided both in management of their travel and coordination of their effort, by the Anti-Xeelee. Use of the Sugar Lumps enabled the Xeelee to consciously manage their own evolution as well as make any necessary edits to the history of the universe so that their projects are unopposed to the maximum extent possible. It is therefore likely that any species whice made a substantial rivaly with the Xeelee were prevented from evolving in the first place, and further that the Xeelee were unable to prevent the evolution of the Photino Birds.