Exultant: Destiny's Children Book 2 Stephen Baxter
Twenty-five thousand years in the future mankind is still locked in its twenty thousand year long war for survival with the Xeelee.
Billions die every day and mankind's best soldiers are children, bred to fight and die. The war has gone well but has now stalled at the galaxy's core, the Xeelee stronghold.
And as we fight what we cannot believe will be the final battle the cosnequences of a war fought in the first few nano-seconds after the big bang are coming to fruition.