Perhaps they had tried to communicate with the birds, Paul speculated; perhaps they even succeeded. But the conflict with the photino birds was so fundamental that communication was meaningless. This was a dispute not between individuals, worlds, even species; it was a struggle for survival between two inimical life modes trapped in a single Universe.

It was a struggle the Xeelee could not afford to lose. They abandoned their projects and mobilized.

The final War must have started slowly. Paul imagined Xeelee nightfighters descending on stars known to harbor key photino bird flocks, cherry-red starbreaker beams shining like swords. And there would be reciprocal action by the photino birds; their unimaginable weapons would slide all but unobserved past the best defenses of the Xeelee.

And the Xeelee must, about the same time, have initiated the construction of the great causal loop controlled by the antiXeelee with its seed pods. At last Paul understood the antiXeelee's purpose: the Xeelee had, with awesome determination, decided to modify their own evolutionary history in order to equip themselves for the battle with the photino birds. Paul pictured a branching of the Universe as the antiXeelee changed the past. The Xeelee, modified and pre-warned, had time in this new history to prepare for the coming conflict, including the construction of the mighty artifact called Bolder's Ring -- an escape route in case, despite all their preparation, the War were lost.

And all the time humans and other races, oblivious to the great purpose of the Xeelee, had scrambled for abandoned Xeelee toys. Eventually humans had even had the audacity to attack the Xeelee themselves, unaware that the Xeelee were waging a total War against a common enemy far more deadly than the Qax, or the Squeem, or any of man's ancient foes.

The Xeelee wars had been a ghastly, epochal error of mankind. Humans believed they must challenge the Xeelee: overthrow them, become petty kings of the baryonic cosmos.

This absurd rivalry led, in the end, to the virtual destruction of the human species. And -- worse, Paul reflected -- it blinded humanity to the true nature of the Xeelee, and their goals: and to the threat of the dark matter realm.

There was a fundamental conflict in the Universe, between the dark and light forms of matter -- a conflict which had, at last, driven the stars to their extinction. Differences among baryonic species -- the Xeelee and humanity, for instance -- are as nothing compared to that great schism.

And, even as the wars continued, still the cancer of aging, swelling and exploding stars had spread. The growth of the disrupted regions must have been little short of exponential.

At last the Xeelee realized that -- despite the deployment of the resources of a Universe, despite the manipulation of their own history -- this was a War they could not win.

It remained only to close the antiXeelee's causal loop, to complete the Ring, and to flee the Universe they had lost.